Since the advent of LiDAR and structure from motion (SfM) techniques, GB-InSAR and thermal imaging, etc. the study of the hazard of failure of the rockfall sources has drastically changed. First, cloud points allow to characterize structures and assess the rockfall source volume distribution by periodic acquisitions, which is fundamental for rockfall hazard assessment. Several studies have shown that volume distributions follow power laws. These distributions are nowadays crucial for real rockfall hazard assessment. However, they have inherent limitations, such as time steps sampling, or fragmentation degree after failure. Such an approach provides for diffuse hazards, i.e., the exact locations of the sources are not known, but also to better characterize the rockfall activity of the different rock source types and structures. When the source is located, the temporal probability of failure must be evaluated. This means that state of stability or rock mass degradation must be assessed. Using remote sensing methods several promising research avenues exist. This can be performed using monitoring rock mass strength degradation via high-resolution 3D tracking of cyclic deformations with hysteresis by 3D point clouds or GB-InSAR. These deformations can result from factors like groundwater circulations, thermal cycles, earthquakes, rainfall, etc. The thermal imaging of shallow rock instability can provide the extend of rock bridges and can be coupled with deformation. Several attempts have been made to extract from 3D point cloud discontinuity set characteristics such as spacing and trace length distributions, but several drawbacks exist such as recognition of traces on point clouds without available surfaces or the true distribution of trace lengths. Nevertheless, more and more solutions are developed. The geological strength index (GSI) can be evaluated using remote sensing such as thermal imaging or discontinuity characterization by 3D data. The GSI can be used to estimate the power-law parameters. One of the key challenges to enhance rockfall sources hazard assessment, it's essential to better understand these processes and their interplay with physical and chemical weathering. Because the erosion of weak rocks, such as marls, may help to understand the thermal and rainfall effects on rock mass degradation. In conclusion, high resolution remote sensing data support the understanding of external forcing on rockfall activity, in particular characterizing volumes distributions and deformations.

The Great Glen Fault (GGF) of Northern Scotland is one of the most enigmatic fault structures in the UK. Despite much previous work, its status, longevity and movement history remain controversial. The British Geological Survey (BGS) are currently undertaking a nationwide project aimed at characterising major faults in the UK. ‘UK Structure’ aims to generate a baseline dataset that will meet the needs of various stakeholders requiring information about faulting history and properties in the UK and its impact on national infrastructure, groundwater resources and geodisposal, for example. The Coire Glas project is a hydro pumped storage scheme with the capability to double the current electricity storage capacity of Great Britain. The ambitious and large-scale civil engineering project will involve tunnelling through the GGF in order to connect the lower reservoir (Loch Lochy) with the new upper reservoir. Detailed characterisation of fault rocks encountered during the project will help to better understand the GGF, and has potential implications for future engineering projects. Here we have devised and applied a characterisation workflow to a suite of fault rocks from the GGF. The workflow includes the application of CT during sample preparation, allowing for preparation of an undisturbed and fully orientated section of fault gouge material. Furthermore, detailed petrology of fault rocks is determined using a range of methods including X-ray Diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), and optical (cold-cathode) cathodoluminescence (CC-CL). The microstructure of the fault rocks reflects a complex multigenerational fracturing history associated with movement on the GGF, indicated by numerous different phases of carbonate and silicate mineralisation as identified using SEM Mineralogic software. These phases include Mg-siderite cements within fault gouge, and late-stage authigenic kaolinite and calcite cements within fractured ferroan dolomite clasts. In addition to detailed petrological characterisation, we intend to carry out U-Pb dating of calcite crystals within fault rocks to determine the age of calcite mineralisation, thus providing a better understanding of the timing of fault movement.

Localised failure in the form of shear localisation bands is always observed in triaxial tests on rocks and other geomaterials. The deformation inside a shear band is usually much higher than its counterpart in the zone outside the shear band, while stresses inside and outside a shear band are comparable, due to equilibrium conditions across the boundary of the shear band. Inelastic behaviour of the specimen is mainly governed by the behaviour inside shear bands and hence should be considered as true intrinsic properties of the material. Nevertheless, traditional practice in analysing and interpreting triaxial test data usually ignore localisation of deformation by taking averaged measurements of both strains and stresses over the volume of the specimens. As a consequence, the use of stress-strain relationships obtained from triaxial tests to represent behaviour of geomaterials is questionable, given they are the averaged quantities and hence cannot truly represent intrinsic properties of rocks and other similar geomaterials. In this study, an approach considering localised failure is developed and used to correctly interpreting and analysing triaxial test results on rocks. The obtained results on stress and relative displacements between two sides of a shear band are considered intrinsic post-localisation behaviour of rocks. They can be used directly for the development of a new generation of constitutive models taking into account localised nature of failure. Both benefits and practical implications of the proposed new approach for obtaining intrinsic properties of geomaterials are discussed and highlighted.

The Capo d'Orlando is a terrigenous formation outcropping in the northeastern part of Sicily (southern Italy). Its deposition is related to the preliminary erosion of basement metamorphic rocks, and subsequent transport through gravitational processes in different sedimentation ba-sins. This led to the formation of heterogeneous deposits consisting in sandstone banks, locally alternating with pelitic and conglomeratic layers. The present research aims to study the sand-stones at the scale of both intact rock, that was analyzed in laboratory to assess their physical - mechanical properties, and rock mass, through field surveys. The achieved results confirmed that although the sandstones are part of the same geological formation their physical-mechanical features are strongly variable.

Heritage conservation is of great importance to society, particularly in light of the recent increase in fires affecting historical buildings. This study investigates the effects of high-temperature exposure on Pedra de Borriol, a specific type of limestone. This rock has been commonly used in the construction of historical monuments in eastern Spain since the 17th century, and it continues to be utilized today, particularly for ornamental purposes. The study analyzes the effects of high temperatures on the strength, mineralogy, and color of this cretaceous limestone. On one hand, it is known that the strength of rocks decreases with increasing temperatures when subjected to thermal treatment. In the case of the limestone studied in this research, a decrease in strength of over 90% has been observed when exposed to temperatures exceeding 800°C. On the other hand, it has been noted that the color of this rock varies noticeably at different temperatures. The significant color changes are directly linked to the mineralogical composition of the rock. At an exposure temperature of 400°C, the natural color of the rock turns reddish; at 600°C, the color becomes gray, and at 900°C, the rock exhibits a whitish coloration. By considering the three aspects of mineralogy, color, and strength, it becomes possible to assess the impact of a fire on a historical monument constructed with this particular rock. Through this analysis, it is possible to (i) estimate the maximum temperature the material has been exposed to, (ii) evaluate the decrease in strength using non-destructive testing methods such as color changes, and (iii) identify the areas of the building affected by varying degrees of thermal damage. The ultimate objective is to investigate the effects of high temperatures on both the ornamental and structural functions of the rock. The results obtained from this research contribute to the advancement of techniques for assessing thermal damage to historical heritage after a fire

Detonating cord splitting is a quite common production technique for dimension stone blocks, in granite and gneiss quarries, where the blasts are usually designed based on local experience. The paper relates to a vibrometric test campaign, carried on in a group of gneiss quarries using accelerometric measurements at proximity to the hole’s rows, both in primary splitting and recutting operations. The purpose of the test campaign was to detect (or to exclude) the possibility of impairment of the commercial stone blocks produced by this technique, to check the validity of the blast design criteria adopted, and to obtain experimental data for predicting the friction conditions at the boundaries of the blocks and their expected displacement. The results highlight the limited damage of the commercial blocks obtained, confirming the validity of the detonating cord as a functional technique to split and slightly move the blocks from their original position. The vibrations due to the blast are also very limited even at a short distance, confirming that the technique is precautionary and respects the quality of the exploited blocks.

Anchored mesh systems constitute a widely adopted protective mitigation measure against rockfall, particularly suitable for highly weathered sub-vertical rock face These systems are composed of steel wire mesh panels combined with a regular anchoring pattern. In this work, we investigate by means of discrete element simulations the mechanical behavior of the mesh with the commonly adopted quincunx-like (or diamond) anchoring pattern, comparing with what we have already found for the square pattern. The effects of the loading condition and the mesh system properties on the out-of-plane response of the system are evaluated and ana-lytical relationships for quantifying the mesh punching resistance and maximum deflection are proposed. The results allow quick assessment of the suitability of the design choices and provide an insight on the force transmission paths during the loading of the mesh system.

It is necessary to obtain reliable estimates of the in situ stress state for the design of any underground engineering project in rock, but it is of paramount importance for safety-critical projects such as deep geological repositories for nuclear waste. It is widely considered that in situ stress is a function of depth below ground surface. This often leads to rock masses being partitioned into depth based domains, but there are no universally agreed and statistically robust methods for doing so. In this paper we present a novel method that uses Bayesian linear segmented regression of Cartesian stress components to probabilistically characterize the variability and uncertainty in the depth of non-crisp stress domain boundaries, and the in situ stress state within each domain. We demonstrate the efficacy of the method using synthetically generated stress data, and then apply the method to overcoring stress measurements obtained at the Forsmark site in Sweden.

Analysis of rock slope stability is a key step on the successful design and excavation of open pit mines and quarries. This study shows the rock mass characterization and the different analyses carried out to assess the stability of the final slope of a calcareous quarry. The studied excavation is located on the near-axis flank of a syncline, in such a way that the stratification set varies its dip from some 40º on the nearest zone of the axis to 20º on the farthest zone, creating a slightly complex geometry. This situation requires a set of different approaches to assess the stability of the slopes. For the studied case, a proposed design of the full open pit quarry was received. All the different possible failure mechanisms of the quarry were identified and analysed using limit equilibrium and numerical methods. West slope, which resulted to be parallel in strike to the stratification, featured a planar mechanism stability problem, so it was analysed in detail and a new stable design was proposed. This paper describes the steps carried out to characterize the rock, the discontinuities and the rock mass, as well as the different approaches used to obtain the stable design.

The stability evaluation of rock masses surrounding large underground caverns under earth-quake effect is an alive and important subject. Under earthquake effect, the mechanical re-sponse characteristics of rock masses surrounding underground caverns are remarkably differ-ent from those under excavation unloading effect. Therefore, it is not appropriate to directly use the methods and criterions that are commonly adopted in static analysis to evaluate the behav-iors of rock masses under dynamic condition. A series of indexes and relevant criterions are included in the system. The indexes of relative displacement, peak stress, depth of damage zone, and rock support stress are proposed as a whole evaluation system. The evaluation sys-tem is then validated in a large underground cavern subjected to earthquake effect. It is con-cluded the system is effective. The presented methods and findings are hoped to provide useful references for other rock caverns with similar stability concerns.

Groundwater flow through fractured rocks was recognized as an important problem connected to several scientific and engineering geological fields, including hydrogeology, rock mechan-ics, geotechnical engineering. Fluid flow in rock masses plays an important role in many geo-logical hazards such as environmental risk. Fractured media are very heterogeneous and the hydraulic and geomechanical properties are strongly dependent on the rock mass spatially varying geometrical parameters. This makes the study of groundwater flow a considerable challenge for modeling purposes in the frame of environmental pollution, especially consider-ing that fractures may act as preferential drainage paths, thus accelerating the transport process. This study aims at shedding light, through a numerical simulation, on the influence played by major fractures on the groundwater circulation in a carbonate aquifer. The numerical model was built in a Q-GIS environment through the FREEWAT plug-in, by considering different scenarios that model the interaction between pumping activity and fracture field.

Rockfall reinforced earth embankments (RPE) are widely adopted defence structures against rockfall, particularly effective for high-energetic or frequent block impacts. Existing design approaches often involve simplifications, as RPE resisting mechanisms during impact has been not yet completely investigated. This study investigates the RPE response at the impact through a series of FEM analyses. Geophysical and plate load tests on an existing RPE are used to calibrate the soil constitutive law of the numerical model. The results of the huge campaign of sensitivity analyses, herein presented, allow to determine the mechanical and geometrical parameters most affecting the structural behaviour.

For underground rock engineering, laboratory testing is performed to obtain objective in-formation about the rock behaviour under compressive or compression-induced tensile fields through biaxial, true triaxial and indirect tensile tests. The ISRM-suggested methods for laboratory testing advocate the implementation of axial loading or strain rates that de-pend on laboratory parameters that are not or only rarely related to in-situ conditions. Near an excavation wall, the tangential strain and therefore strain-rate decreased with increasing distance from the wall. Due to the complexity of physically assembling a multi-platen ser-vo-controlled machine, the influence of uniform and non-uniform tangential strain rate distributions on the mechanical behaviour of brittle materials is rarely tested and is as-sessed here by using the software PFC2D. The mechanical responses for loading with two tangential strain patterns or strain-rate distributions are compared in terms of cracking pat-tern, stress-strain curves, bulking strain and related displacement at the excavation surface.

The selection and the design of rockfall protection works often relies on the evaluation of the energy involved in the possible phenomena. This requires the identification of a characteristic energy value: this is usually done through numerical simulations of block trajectories, both in 2D and 3D, from which the actual reference value of total kinetic energy at a specific location along the slope can be identified. The experience and expertise of the designers play a crucial role in the choice of the input parameters: the process heavily depends on the choices of the reference values themselves, making the approach highly deterministic and often empirical. A possible alternative design approach would rely on the probabilistic description of the phenomenon, through the use of distributions of the most relevant parameters, instead of deterministic values. The method proposed here is based on the identification of the characteristic In situ Block Size Distribution (IBSD) of a rock mass identified as rockfall source area, and 2D numerical simulations of block paths. From a significant number of these simulations, the probability distribution of the design parameters is obtained: in the case of passive protection works, such as flexible barriers or embankments, this corresponds to the definition of the Total Kinetic Energy probability distribution, which can support the identification of the energy level the structure is required to withstand, and to the Bounces Height probability distribution, which can direct the choice of the height of the structure. The significant advantage of this probabilistic approach lies in two key features. The first one is the rigorous statistical treatment of the parameters involved, as required for the definition of the IBSD: this provides in return a significantly reliable method, devoid of empirically based choices, yet simple and quantitative. It is also important to note that the probability distributions of the design parameters can still be used in a traditional design approach to quantitively justify the choice of characteristic values. On the other hand, describing the phenomenon in a probabilistic way also allows for methods based on failure probability to be employed. The second advantage is the possibility to define generalized acceptable levels of residual probability, through which standardize the selection of the design parameters. In this way, the designers, who assume a significant responsibility when dealing with these choices, could be provided with a tool to deal with possible predictable consequences.

This paper presents a methodology to identify key blocks in highly structured rock masses. Calculating the stability of these key blocks is critical to forecasting geotechnical risk in terms of potential failure volume and runout distance. Key blocks are determined using structural mapping data from photogrammetry data acquired by drone flyovers. The Factor of Safety of key blocks is then calculated using limit equilibrium methods. Any key block with a Factor of Safety less than one is then systematically removed from the slope to determine the maximum potential volume of slope unravelling once the key block is removed. This information is then used to determine potential runout distances. Sections of slope predicted susceptible to failure (i.e. Factor of Safety less than one) can be the focus of proactive monitoring or hazard control (e.g. through the forward instalment of barriers, exclusion zones, etc.).

The problems of collapse sinkholes (simas) that have affected the population of Alcalá de Ebro are very old. Since 1980, both the SGOP and the CEDEX, among others, have worked on the investigation of an area located at the entrance of the Population where there have been several subsidences (collapses), affecting a street, the flood defense area of the Ebro River, and some houses. Since then, different recognition techniques have been applied with the intention of assessing the geological-geotechnical model of the affected environment. All the information obtained in previous studies was reviewed and expanded, to improve correlation and the scheme of the internal structure of the subsoil was completed by means of a geophysical profile based on techniques: Cross-hole and MASH. The resulting profile after incorporating all the data obtained in the different research reports carried out/compiled, allows an interpretative model to be reached and the following conclusion to be obtained: The basis of the problem that facilitate the generation of sinkholes-chasms at this point in Alcalá de Ebro is located at a level or stratum, from 4 to 6 meters in relative thickness, located at a depth of between about 14 (from the access street to Alcalá), which is formed by an alternation of highly soluble rocks: massive gypsum ( usually in the form of nodules), glauberite, and possibly thenardites and epsomites. The most relevant thing is that levels or layers of salt (halite) have also been recognized. The apparently affected surface made it possible to evaluate consolidation solutions that were initially based on injections of expansive resins and later on injections of low mobility mortar. The latter were carried out in two phases during the years 2017 and 2018. The aforementioned “mortar columns” descended between 21 and 23 meters until they crossed the affected area and entered firm ground. Once the treatment with mortar was carried out, the embankment was reinforced, on the surface, using flexible geogrids, but with high tensile strength. At present (almost 5 years after carrying out the consolidation works), the results have been monitored, carrying out high-precision level and measurements with terrestrial laser-scanners. Geophysical research work continues to be carried out using Ultra GPR georadar and electrical tomography. The apparent results obtained are positive and allow evaluating a technique of consolidation and improvement of the terrain, in a particularly sensitive point affected by frequent subsidence and collapse processes.

Coal mining in the eastern part of Saar district (Germany) caused numerous seismic events. After a ML = 4.0 event (93.7 mm/s PPV) in 2008 mining was stopped for good. Coal has been extracted by the longwall mining method at depth below surface of 1600 m. During extraction the mine water was kept below the deepest seam by pumping at central shaft. In 2013, the pumps were shut down and the water level in the shaft rose. Seismic events occurred immediately and the water level in the shaft was kept from 2015 on constant at 300 m higher compared to the level during mining. Two cluster of mine-water induced seismic events were observed. One cluster is located around the panels in the area where seismic events occurred during mining, which is no surprise. Another cluster is in the undisturbed rock mass away from longwall operations, i.e., in an area of approximately 6 km² surrounded by separate fields of panels. The only conduits for water in that otherwise undisturbed area/ volume are several 6 m x 5 m gateways directly connected to a shaft outside that area. Major faults are present there and the mining authorities wanted to know whether seismic events may occur with further rise of mine water in the shaft. This paper describes the methodology for arriving at estimates of future seismic events caused by elevated pressure from mine flooding. Substantial numerical modelling was necessary for estimating the spatial water pressure distribution over time. Fault planes from focal analyses were compared with known discontinuity orientations at different scales. Finally, based on the concept of the mobilized friction angle of discontinuities, it was concluded that the major faults will not contribute to the seismic events during further rise of mine water.

The use of 3D slope stability models for assessing risk and opportunity across various time horizons from the life of mine, five-year (5YP), two-year (2YP) and quarterly or three-month (3MP) mine plans is becoming common practice. The goal is to improve mine design reliability, and as an industry, achieve digital twins for mining and slope stability. These improvements are facilitated by faster computing and user-friendly 3D slope stability software as well as in-creasing monitoring instrumentation deployment in open pit mines. This paper investigates the use of Hu coefficients for simulating pore pressures relative to pre-defined phreatic surfaces or groundwater tables to facilitate rapid updates to 3D slope stability models based on updated pore pressure data obtained from a network of vibrating wire piezometers (VWPs). It also dis-cusses pore pressure sensitivity checks for risk management, and the benefits and limitations of this approach.

In 2010 a process was started to stablish international standards on geotechnical instrumentation under the ISO umbrella. General concepts of these standards were published in 2015, the first part on extensometers in 2016, the inclinometers document in 2017, total pressure cells and piezometers were published in 2020 . All these documents have been published in English and French all over the world. In Europe these documents have been published under EN_ISO 18674. Part 8 on the use of load cells to measure load is in the last steps of the approval process and probably Will be published this 2023. The aim of the paper is to show the development and specific role of these standards on the use of geotechnical instrumentation.

The Mediterranean region has witnessed major infrastructure projects in recent decades, with multiple tunnels usually being constructed using NATM (New Austrian Tunneling Method). The essence of this method lies in continuous observation of deformations and geological assessment, allowing for optimization of the tunnel support system. However, the presence of BIM (Block-in-Matrix) rocks implies significant challenges to application of NATM. The BIM rock exhibits chaotic, heterogeneous, and often highly unpredictable geological structure. This makes it impossible to assess the quality of the rock mass using conventional categorization methodologies such as RMR (Rock Mass Rating) or GSI (Geological Strength Index). The challenges of tunneling in BIM rock were encountered in 3,6 km twin tube tunnel Golubinja, which is currently under construction in Bosnia and Herzegovina. Geological profile was initially assumed to consist of medium strong to weak, moderately to highly weathered shale, siltstone and sandstone of Jurassic age. During the construction phase, a significant discrepancy between the predicted geology and the actual conditions was encountered. The actual conditions were characterized by the presence of ophiolite mélange and ophiolithic crust sheets formations leading to a BIM type of material in which the matrix was formed of siliciclastic strata (graphitic phyllite) and blocks were formed of sedimentary and metamorphic rock. The designed short axis distance between the twin tunnels of 25 m led to a strong interaction between the tubes and presented an insurmountable obstacle for tunnel construction. Issues such as collapse of the primary lining and general instability were observed along the extensive sections of the tunnel. The reevaluation of the geological profile, increasing length of the axis distance between the tubes, and implementation of secondary lining as part of the support systems were carried out in order to enable buildability of the tunnel for given conditions. This paper presents key aspects of Golubinja tunnel construction including design approaches and remediation measures to overcome challenging BIM rock conditions.

This work focuses on obtaining and updating an inventory map of active landslides in the region of Sierra de Cartagena-La Union (Spain), a mountainous mining area in southeast Spain, by integrating space-borne InSAR and airborne LiDAR techniques. Ascending and descending Sentinel-1 InSAR datasets were processed to obtain LOS displacements. Moreover, open-access, and non-customized LiDAR point clouds were processed to analyze surface changes and movements. Then, active deformation areas (ADA) maps were semi-automatically derived from the InSAR and LiDAR results by using ADATool. The influence of rainfall was analyzed in detail by means of InSAR time series. The results not only highlight the effectiveness of these two remote sensing techniques (i.e. InSAR and LiDAR) to acquire inventory maps of active landslides in mining zones, but also emphasize the key role of rainfall as an important trigger for landslides.

The rains registered in Leon (Spain) during December 2019 created several problems on the railway platform: Line 130 Venta de Baños-Gijon, Section: La Robla - La Pola de Gordon. Damages were at the P.K. 26+700, where rockfalls happened coming from the rocky front located above the railway track. The rocks that come from the top reached the railway platform. A huge rock of approximately 50 t has exceeded the railway and has stopped on the edge of the town Puente de Alba. There are also some rocks, weighing slightly less than 10 t, which have remained next to the track. A statistical analysis of rockfall was done, to define locations of the mitigation measures and evaluated other practical solutions. Finally choosing the installation of the following systems: Rockfall drape system with TECCO® G65/3 high tensile-strength steel mesh, with horizontal reinforcement ropes and Rockfall barrier, 8 m high and energy absorption capacity of 8,000 kJ.

Wire meshes employed in secured drapery systems are constantly exposed to atmospheric corro-sion, resulting in diminished durability. The durability depends on the aggressiveness of the envi-ronment, unique to each location, and the protection of the wire, which is often poorly defined in projects. The applicable regulations include a classification of different environments (C2, C3, C4, C5, CX) based on their corrosivity levels. The class of environment serves as a technical character-istic to specify the necessary wire protection to ensure the stipulated service life. Steel wire prod-ucts typically have two types of protection: galvanic coatings, delivering electrochemical safeguard, and organic coatings, which create a physical barrier from oxygen. This article examines the perti-nent regulations, analyzing durability tests such as salt spray test and Kesternich test, different alloy alternatives, the projected service life for each environmental classification, and a case history re-garding this topic.

Many excavated weathered rocks have good initial stability but lose geomechanical properties until have behaviors similar to some soils, causing collapse of shoring. This is an analysis of different temporary shoring of excavations and their effectiveness reviewed with monitoring. The analysis reveals the relationship between excavation height and deformations. Likewise, it is observed that the incidence of the excavation stages and geometries has a greater impact on the deformations than the stiffness of the applied support.

Potash mining in Germany is thriving since more than hundred years, however reserves are limited, and many deposits will reach the end of its lifespan within the next decades. A new mining concept has been established to increase the lifespan of the mines and maximize the extraction rate of conventional mined potash deposits. The concept of secondary conventional mining utilizes the reduction of the dimensions of pillars to gain additional high quality crude salt. The supporting effect of the pillars is compensated by backfilling of the mined excavations, supported by a comprehensive long-term monitoring concept. The process of maximizing extraction rate with secondary conventional mining starts with mining of the pillar edges. The developed cavity is backfilled with rock salt (or residual material from the manufacturing). A backfilling grade of 90 % is aspired. In a next step the remaining pillar is excavated, leaving two small pillars at each end, which serve as short-term roof support until the remaining excavation is backfilled. With this procedure pillar after pillar are excavated until the whole mining area is backfilled. In preparation of this mining process rock mechanical investigation is done to proof a save mining process. It contains of a numerical modelling and an observation program. The numerical modelling bases on precise rock mechanical 2D and 3D models. The calculation evaluates possible hazards like pillar or field collapses and predicts the expected rock mechanical behavior. Then latter covers the mining induced effects to convergence and their impacts to barrier integrity as well as surface subsidence. The results show that the stresses in the barriers doesn’t endanger their integrity and the predicted surface subsidence is compatible with their normal use too. Bases on these results a monitoring concept is developed to observe the real rock behavior. It includes the development of convergence in the mining field, the released energy during and after the second mining process as well as the observation of surface subsidence – all bases on advanced observation methods. The comparison of the monitored results with the numerical prediction supplies a robust basis for a save mining process.

A massive rockfall event took place at the very entrance of a steep and large Đerdap Gorge on the Danube River in Eastern Serbia on 12-13^th of December 1974. Detailed engineering-geological examination of the site was undertaken at the time, but the event was never fully reconstructed. With the ascent of new surveying and monitoring technologies, and their greater availability in recent years it became possible to revisit such historical events and completely back-analyze them. Otherwise, the Gorge itself is rather active and constantly hosts minor rockfalls and other instabilities. An important international route passes along its base, where despite preventive and protective measures it remains highly exposed to rockfalls, whereas the river, i.e., the artificial lake itself, and the downstream hydropower plant and dam could be endangered by massive events, like in the 1974 when one third of the Danube River profile was dammed. The said event was triggered in an abandoned limestone quarry named Joc, arguably by several preconditioning factors: draw-down effect due to filling of the Đerdap lake that took place in 1972-1973, adversely oriented caverns subject to progressive failure, disturbed rock by heavy blasting in the past, lubrication along the adversely oriented joint set. In spring 2023, a field campaign targeted at ground surface mapping of the wider area was undertaken using advanced geodetic equipment, comprising of UAV Wintera and Mobile LiDAR scanner Leica Pegasus. The objective was to re-map the entire north face and surrounding topography and reconstruct the rockfall. The resulting point cloud depicts an irregularly jointed rock mass, likely disturbed by heavy blasting. The location of the source area was determined from the available field photos, and suggests that one large feature, placed amidst the slope, about 100 m above the road level was detached. It has been severely deformed and fragmented along the runout, so it has been transformed into a pile of rubble with large sized boulders. Total volume was estimated to 250,000 m³. The reconstruction was performed using a variety of tools, starting from simple 2D and 3D models that implement friction cone theory, to robust 3D models that consider complex geometry of collapsed material and detailed ground relief. Expectedly, robust models were more successful in reconstruction of the event, which was validated on the basis of known runout reach and debris height.

Urban sites in highlands or associated with rocky areas are common, giving them an admirable landscape richness and constituting a relevant part of their identity. However, this uniqueness is closely related to the risk posed by the degradation of rock formations, which generally results in the falling of blocks or, in the most severe cases, in landslides. Only in the past year, this phenomenon has occurred in locations such as Mijas, Almogía or Ardales in Spain. This article takes the example of Alcalá la Real (Jaén) to present a process and analysis model to quantify the geological risk factors in scenarios of rockfalls such as the one that took place in this town, which enables the assessment of the possible actions to be carried out with the aim of reducing these risks. It is important to remark the fact that, in most cases, one of the main premises is that the action should not have a major impact on the landscape. The underlying cause of the study carried out in the aforementioned municipality of Alcalá la Real was the fall of a large block on Calle Utrilla on a Sunday in summertime, as well as the risk of a further landslide affecting the pathways and houses located in the lower part of the hill. Once the block had detached, its fall by gravity put at risk the houses located at a distance of 125 ml. on a slope with a difference in height of 43 metres. The detached block had a volume of about 72 m³ and an estimated weight of 190 tons. The slope from which this block detached is formed by a level of bioclastic calcarenites supported by soft sandstones, sands and wall clays. The state of the outcrop before the instability occurred was conditioned by the strength of the material supporting the calcarenite levels and the fracturing system of the latter. The study considered several actions to be undertaken given the risk that more blocks could detach, quantifying and zoning the risks for each of the proposed actions.

The natural and cut slopes of a segment of the Dharasu-Uttarkashi Roadway (NH-108), located in the Lesser Himalayan Zone in India, have been studied adopting a multi-parametric integrated approach in terms of (1) distribution of magnitude of natural slope (2) engineering geological properties of intact rocks and rock masses, (3) kinematic analysis of slopes, (4) documentation of existing slope failures (5) rock- microstructural implications, (6) multiple geomechanical classifcation of slopes and (6) implications of active tectonics as deciphered from Neotectonic indices. Assessment of stability of slopes based on the combined study of the above parameters has been performed for twelve locations (L1−L12) on the road-cut sections where the slopes mostly have not yet failed. Magnitude of natural slopes overlooking the road section attains peak slope class of 41°−50°. Kinematic analysis characterizes the intact slopes in the above locations to possess conditions of wedge and toppling modes of failure, either in single or as combined. Existing failed slopes conform to combinations of planar, wedge, toppling and shallow circular failures. Rock microstructural study reveals development of strong shear-strength-weakening foliation anisotropy in the phyllites and schistose quartzites of the slopes that evidently serve as avenues of groundwater percolation and seepage and can promote failure along water soaked foliation planes that ‘day-light’ on the road-cut slopes at locations L1, L8 L9 and L10. Based on Geomechanical classifcation systems applied to slopes including Continuous Slope Mass Rating, Q-Slope and Hazard Index, new stability charts have been developed that classify the slopes at each location to be one of the three types: severely unstable, unstable or stable. Based on the new stability charts, road-cut slopes at all twelve locations were found to be unstable and slopes at three locations−L7, L8 and L10 were observed to be severely unstable, particularly hazardous and require immediate mitigation. From the erosional landscape of the study area, using several geomorphometric elements including ruggedness number (R_n), ratio of valley floor-width to valley-height, (V_f), stream length gradient index (S_L) and Hypsometric integral (H_i), an index of neotectonic activity (I_at) over the study area is obtained with an estimated value of 1.50 that indicates high neotectonic activity. Such high value of neotectonic index correlates with the high recent seismicity events documented from the zone containing the study area. Corresponding high neotectonic activity is expected to create steeper slopes due to deeper incisions and would potentially trigger failures in some of the currently stable slopes in the area.

Slope stability analysis is crucial for transportation projects in hilly areas, especially for road or tunnel portals. Various methods exist to assess slope instability, such as field-based, limit equilibrium, Numerical, and rock fall simulation. Among these, the field-based Slope Mass Rating (SMR) method is popular for initial assessments. In this study, a Windows-based Python application was developed to calculate SMR efficiently. The app quickly evaluates slope instability using provided data and allows users to input direct Rock Quality Designation (RQD) or estimate it based on joint spacing. It automatically calculates F1, F2, and F3 factors for all joints and identifies formed wedges due to joint interactions. The app generates detailed reports including joint attributes and ratings, aiding in slope stability interpretation. This user-friendly tool enhances slope stability analysis for project planning and generates technical reports for better project understanding.

Waste dump failures in coal mining pose significant safety risks, necessitating detailed post-failure studies alongside pre-failure deformation study. The post-failure studies evaluate the mobility of the failing mass, measured by parameters like runout length and width (i.e., runout characteristics). The understanding of the mobility of failing mass will help design a buffer zone around an overburden dump to restrict worker and machinery movement. This study, using a laboratory-scale debris flow flume, explores the effect of the composition of overburden dump on runout characteristics and the shape of debris flow fan. The findings of the experimental investigation suggest that while changes in relative proportion of fines and coarse particles (F/C ratio) affect both runout length and width, the effect on the aspect ratio may not show a straight forward pattern. The complex changes in aspect ratio imply that the overall shape of the debris flow fan may not be solely determined by the F/C ratio.

Elastic properties of rocks like Young’s modulus and compressional P-wave velocity are vital for understanding their stress-strain response in mining and rock engineering applications. Traditional methods for determining these properties involve labor-intensive, expensive and time-consuming. To address these challenges, this study proposes a novel predictive method. It utilizes a multi-layer perceptron feed forward neural network (MLP-FFNN) trained on grinding characteristics of ball mill to predict Young’s modulus and compressional P-wave velocity in sedimentary rocks. Laboratory experiments on limestone and dolomite samples generated extensive data, enabling development of prediction models using the proposed MLP-FFNN. The developed models demonstrate high predictive accuracy (R values: 0.952 for E, 0.987 for Vp) in training and good generalization (0.866 for E, 0.9707 for Vp) in testing, along with low Root Mean Squared Error (RMSE) values. These findings underscore the efficacy of neural network models in predicting E and Vp from grinding characteristics of ball mill.

Extraction of coal is done by both opencast and underground method of workings. The amount of overburden removal has increased significantly as the share of opencast coal mining has increased to ensure maximum recovery and greater depths. The accumulation of the removed overburden material as dumps at greater heights for the minimum ground cover area is an important task in the opencast mines due to which the dumps tend to fail. A dump failure can pause mining operations, endanger personnel and damage equipment. In some cases, due to lack of dumping space, the overburden dumps are laid above the underground excavations. The stability of the dumps over the old underground workings is a difficult task because of the stresses that are already developed due to the underground excavation. Therefore, it is paramount to study the stability of the slopes in this zone particularly when there was an old inaccessible extraction present within this zone. In this article, the prediction of stability of overburden dumps above the underground workings are studied by means of underground longwall working dimensions. A two-dimensional finite element analysis method is used in predicting the stability of overburden dump using RS2 software of Rocscience. Strength Reduction Technique is used for determining the factor of safety (FoS) of the overburden dump. From the modelling studies, it is summarized that the stability of the overburden dumps is being affected due to the presence of underground excavation with a vertical deformation of 0.0564m (56.4mm) for the critical strength reduction factor 1.12.

The Grassy Mountain mining project owned by Paramount Gold Nevada Corp. in the state of Oregon, USA has been developed for a Cut and Fill underground mining methodology with cemented backfill (CRF) operation. The present study analyzes the main variables involved in the manufacture and subsequent performance of cemented backfill, through a sampling process involving 12 CRF specimens prepared and tested by MetaRock Lab under the supervision of GMS, in order to obtain the UCS strength values of each one. Thus, 6 CRF specimens with 5% cement and 6 specimens with 7% cement were prepared, which in turn were subdivided into a curing time of 14 and 28 days. From the results of the UCS tests, the variables of cement percentage, sample density and days of curing are directly related to the strength of the CRF, obtaining better performances as these values increase. Finally, based on the benchmarking study, the performance of the CRF samples, according to the mix developed and proposed by GMS for the Grassy Mountain project, is within the expected range. The values for resistance, which is the main indicator to be highlighted, are in accordance with what would be expected according to the characteristics of the mixture, obtaining a maximum resistance of 6.14 MPa.

Due to rapid and extreme climate changes, in mountain and hilly regions infrastructures and people are more often treathened by rockfalls events. Falling boulders can have extremely high speeds, and these events involve a complex pattern of movement (e.g. detachment, fall, rolling, sliding, bouncing, etc) of one or more rock fragments. Rockfall Protection Embankments (RPE) reinforced with geosynthetics proved to be a safe measure for protecting people, structures and infrastructures from rockfall events, designed to absorb even very high impact energy (up to 30,000 kJ). RPEs can be constructed in various shapes and sizes, with different reinforcements (geogrids, geotextiles, geostrips, steel wire meshes, etc.) and facing materials (wrap-around, gabions, tires, etc.). The vast majority of existing RPE structures have been designed with basic approaches, considering dynamics only to a minor extent. The Authors have then developed a new analytical design method which consider the effect of all the variables playing a role in the resistance to penetration on the uphill face and the resistance to extrusion on the downhill face, in order to finally compute approximate yet consistent values of the penetration depth and of the extrusion length; hence the designer can quickly try different solutions and finally select the best combination of design variables which afford to respect all design limits and Factors of Safety. To the Authors’ knowledge, at present this is the only design method for RPEs which allows to take into account all the parameters contributing to the penetration and extrusion resistance, including the type and properties of geosynthetics, the layout and spacing of reinforcement in longitudinal and transversal direction of embankment, the type of facing, the properties of the fill and the geometry of the embankment. A back analysis of full scale tests is used to validate the presented design method.

Cheves Hydropower Project is in the Central Peruvian Andes, N of Lima that generates 825 GWh/year since 2015. The project includes approximately 20 km of tunnels and two caverns. The construction was done mainly in intrusive and the metamorphic rocks; generalized rock burst conditions took place, recording more than 850 stress-events. These events boost themselves in the presence of stiff rocks and geological structures, happening either at the face excavation or behind the face in the reinforced sections. The paper analyses all the factors related to the occurrence of stress-events: overburden, horizontal in situ stress, lithology and stiffness, joint sets and related structures and induced stresses; providing useful criteria, enabling designers to collect data and make some correlations that may be useful for other projects.

The Terradets Gorge is essential in the Catalan linear land infrastructure transport network. It serves as a natural boundary between Noguera and Pallars Jussà, facilitating a vital north-south connection for trade and tourism. In this area roads and railways traverse the gorge, despite facing elevations of rock slopes up to 500 meters. Recent incidents have highlighted their traffic vulnerability to rock falls and debris flows. Both administrations, Roads and Railways of the Catalan Government, have concurred addressing these chal-lenges between 2022 and 2023, enabling the comparison between infrastructure mainte-nance policies and revealing similar solutions for protection and mitigation. The experi-ence underscores the effectiveness of collaborative management in the face of geological risk in priority infrastructure corridors, where both authorities coincide. Sharing resources and strategies not only reinforces efficiency but also promotes cooperation among entities, enhancing resilience against future challenges

This paper presents a procedure of ill-posed problem back analysis of multiple landslides to de-termine the reliable shear strength parameters of rock mass. This procedure includes field in-vestigations, determination of instability mechanism, definition of collapse surface on the rep-resentative section, limit equilibrium stability analysis for variable shear strength properties, and limiting the range of possible answers. This procedure was applied for two individual complex translational-rotational landslides in Jajram Golbini No.07 mine. The investigations indicate the similarity and spatial correlation between the mechanical (shear strength) attributes of sliding surface of both landslides. This provide an opportunity to establish two equations for determination of shear strength parameters. Then, the cohesion and friction angle of rock mass were determined by solving these system of equations. The results of back analysis provide very useful information about shear strength parameters of rock mass and fault that can be ap-plied for reliable redesign of mine slope.

During the 19th century, coal mining in the underground of the Belmez urban area has caused subsidence with small cracks that are balanced by jumps of 1cm/year. Recently, a NW–SE direction cracking with distension of the mining roof terrain has been actived by the drainage of a mining operation and the emptying of two water deposits. A Namurian reverse fault that crosses Belmez on the surface has been reactivated as a dextral shear in the Kimmeric phase. By City Council request, this problem has been studied by comparing the natural tensions in the environment. Using a innovative Seismic Geotechnics, 30 m long NE-SW multi-channel reflection profiles are created for the seismic inversion of guided waves that allow to know the inelastic deformation of the terrain. Beneath this Namurian fault, there are the work-ings of coal layers from 40 m depth. The natural stresses, elastic moduli and friction angle have been obtained with the P and Svertical waves, which have been plotted, together with the inelastic Sradial geostatistics, up to 40 m depth.

In high-resolution research with Seismic Geotechnics, compression waves and three orthogo-nal shears are generated to obtain velocities based on the times of the reflected bands. Using an inverse process, the time domain is transformed into depth, up to 100 m, and distortion models are provided with underground images of natural stresses, friction angle, permeabilities, and elastic and inelastic modules using vertical and radial shear waves. By partitioning the energy of seismic waves at a discontinuity or interface, the initiation of rupture is proposed. Through the impact of energy on the heterogeneous ground surface, constructive waves in phase are reflected at the interface when impedance increases with depth and frequency remains constant. If imped-ance decreases with depth, the partition of the reflected wave presents a longer wavelength and is not constructive; it is out of phase, leading to tension and shear that generate pre-ruptures as deformation increases with the absorption of wave amplitude, resulting in the loss of contact be-tween particles. Results from the sliding model and classical mechanics can be compared; they are also applied in rock compression tests.

The Poggio Baldi Natural Laboratory, jointly managed by Sapienza University of Rome's Department of Earth Sciences and NHAZCA SRL, utilizes cutting-edge instruments like LiDAR, drones, radar, and more to monitor a critically stable rock scarp. It aims to understand connections between rockfalls and factors like geo-structural arrangements, thermal effects, seismic activity, and weather, with the goal of creating an early warning system. Research at the lab focuses on geo-structural characterization, analyzing block failure potential, and assessing rockfall hazards. High-res point cloud data and orthoimages help determine discontinuity orientation and rock block volumes. An innovative algorithm enables pixel-based stability analysis. The study compares data from different sources for analysis suitability and identifies active rockfall zones through 3D change detection. Simulations in these zones evaluate potential hazards. Overall, the lab's multidisciplinary approach using advanced tech enhances our grasp of rock slope dynamics in susceptible hilly regions.

The Scaled Span method is an empirical approach for calculating the stability of mine crown pillars: To determine the stability of the rock bridge between the void and the ground surface. It is a methodology that was born in Canada (Carter, 1988) at the end of the 1980s due to a series of problems and subsidence produced by sinkholes and collapses of shallow abandoned mines. The methodology has been refined over the years and has been applied in numerous countries, such as Canada itself, Austria, Spain, Peru, etc. The database has been increasing and the graph of this method makes it possible to establish both the degree of stability and the possible interventions to be carried out in the upper part of the mine or tunnel (since it has also been applied to shallow tunnels). The methodology uses the rock quality index Q and the dimensions of the void. Scaled Span means that the actual width of the cavity is “scaled” or weighted by other parameters such as rock thickness, length, etc. Volcanic caves or lava tubes are often shallow cavities on which buildings and infrastructures are sometimes built, and many of them are also visited by tourists. It is important for this to carry out an analysis of its stability. The most widely used approximation for the analysis of cave stability is the Q index (Jorda, 2016) but it has many limitations since it only considers geometrically the width of the cavity and not the cover thickness (with the exception of the SRF parameter). cave length, among others. For this reason, the scaled width is a good analysis methodology. In the present investigation, the use by its authors is compiled and extended to various volcanic caves in the Galapagos and Canary Islands, and it is concluded that it is a more realistic methodology than that of only Q-span and that it also provides reasonable protocols to follow for access or impediment to the cave.

In 2021, the Tajogaite volcano on La Palma (Canary Islands, Spain) emitted over 200 million cubic meters of volcanic materials, in the form of lava flows, lapilli and ash. Rebuilding damaged infrastructure, estimated in 1,676 buildings and 73.8 km of roads is a crucial priority. Additionally, it is important to explore potential uses for the products emitted by the volcano. Due to their basaltic nature, volcanic slag, lapilli and ash are suitable for manufacturing building materials such as cement, concrete, blocks or bituminous mixtures. This study focuses on the preparation of concrete tiles using products from the Tajogaite volcano. For this purpose, a laboratory-scale manufacturing procedure for concrete tiles was developed, with the premise of being as sustainable as possible, requiring low energy consumption and minimizing the emissions and waste generation. Various dosages of volcanic material were tested in order to check how it affects the samples performance, as well as to optimize the manufacturing process. The obtained materials were characterized using standard testing methods. Standard UNE-EN 1339 was used as a reference, which specifies the materials, properties, requirements and test methods for cement bound unreinforced concrete paving flagsr. The results of flexural strength tests indicate promising prospects for using the volcanic ash in the production of concrete tiles. However, further research is required to enhance products performance.

The Canary Islands is an archipelago of volcanic origin located in the northern Atlantic Ocean about 100 km from the coast of Africa. Numerous eruptive processes took place during its formation, emitting a large volume of volcanic material. The inhabitants of these islands have known how to take advantage of this resource, and historically, lithologies such as trachytes, basalts, trachybasalts, tuffs, ignimbrites or phonolites have been widely used as building stone. At present, the number of active dimension stone quarries is very small and most of them are concentrated in the islands of Tenerife and Gran Canaria. In the southern part of Tenerife, a pumice tuff known locally as "Canto Blanco" and a group of ignimbrites, with different tonalities, belonging to the lithological unit "Ignimbritas de Arico" are exploited. The extraction of these ignimbrites is carried out by the "Guama" quarry and are marketed under the name "Piedra Chasnera". Fracturing is one of the most important factors for assessing the suitability of a rock mass to provide commercially sized blocks for further processing. The main parameters to consider in a study of this nature are the direction of the joints and their distribution in sets, which define the fracturing pattern, and the spacing which controls the dimensions of the blocks in the rock mass. The main objective of this study is to evaluate the quality of the rock mass of the ignimbrite deposit of the "Guama" quarry. Firstly, given the importance of knowing the joint system to ensure profitable production, the main joint sets in the side wall of the quarry were identified. This evaluation is critical because the quarry owner plans expend the extraction as soon as the upper levels (paleosoil and topsoil) are removed. Secondly, the current exploitation front was analysed by characterising the discontinuities. By measuring the direction and length of the joints and using 3D Block Expert software, the spatial distribution of the fractures was assessed, which allowed to establish the size and volume of the effective blocks, i.e., defined by the natural fracturing.

The identification of rock mass discontinuities and their plane orientation is crucial for determining the characteristics of rock masses. Traditional methods of joint trace surveying can be challenging, time-consuming, and hazardous. However, non-contact measuring techniques offer the advantage of generating accurate objective records of rock masses and enable the measurement of discontinuities from digital surface models and 3D point clouds of outcrops without direct access to the rock mass and associated constraints. An innovative approach for identifying discontinuity planes in rock formations using 3D trace data has been presented in this paper. The concept of curved and straight traces has been introduced, with a curvature index indicating a trace's accuracy in representing its discontinuity plane. Additionally, co-planar traces have been identified by analyzing intersecting straight traces, further contributing to discontinuity plane determination. The methodology's effectiveness has been established through validation using a predefined 3D trace lattice resulting from discontinuity planes with known orientations on a 3D digital rock outcrop model. The methodology has then been applied to analyze 3D trace data from an actual rock outcrop, with successful results. The algorithm enables swift identification of main joint orientations, and this study represents an important advancement in the characterization of rock mass structural properties.

The area of Ollon, Switzerland is regularly subject to different ground instability phenom-enas like landslides due to the nature of its lithology. It is mostly composed of weathered gypsum and anhydrite. This study aims to investigate and characterize the causes of the landslide in Ollon in 2021 by analyzing topographic, historical, geological, and hydrologi-cal data. The last landslide occurred recently on the 1st December 2023.Our analysis ob-serves that the landslide was triggered by geological superficial soil alteration that goes along with a series of rainfalls. The investigation showed that the geological characteristics of the area, including the fast alteration process and steep slopes contributes to a high sus-ceptibility and frequency of landslides in this area.

This study delves into the utilization of an innovative numerical modelling approach to investigate the impact of reinforcing pillars on their strength and stability. Existing case studies in the literature have demonstrated that various methods such as tendon installation, pillar strapping, and the application of shotcrete or thin spray-on liners are commonly employed for pillar reinforcement. However, there is a notable absence of a well-defined methodology for selecting the appropriate support type or determining the necessary support capacity. Consequently, despite the implementation of substantial support measures, certain mines continue to experience pillar collapses. The impact of pillar confinement on a mine wide scale can be analysed thanks to a limit equilibrium model, that was built into a displacement discontinuity boundary element program. The model that incorporates confinement along the pillar's perimeter to replicate how the support interacts with a failing pillar. As part of this study the effects of confining a pillar were analysed and are shown to accurately predict that increased confinement results in a reduced extent of pillar failure.

A comprehensive geotechnical investigation program including geophysical well logging was implemented at an iron ore deposit in Uzbekistan, which targeted at gaining parameters for resource/reserve estimation and mine planning. The deposit represents an asymmetric, approximately ellipsoidal elongated body of about 4.5 by 1.8 km in size. The ore body of vanadiferous titano-magnetite-rich clinopyroxenite is surrounded by metasedimentary strata that form a north plunging synclinal structure, and crop out at three sides of the deposit. Evaluation of the obtained geotechnical data revealed that the project site is generally characterized by significantly varying rock mass conditions. Host rocks are inhomogeneous, foliated and the mechanical properties are directional. The different strata of the surrounding metasediments show high diversity of rock mass properties. For the evaluation of the pit slope stability, kinematic as well as deterministic and probabilistic analyses and a sensitivity analysis were made. In addition to the investigation of potential block failures along discontinuities in the benches, numerical modelling was conducted for the overall pit slopes to evaluate final pit wall stability in the design sectors and assist the mine planning and optimization. It was found that the maximum possible final pit wall angles depend less on the conditions of the ore body rock mass, but essentially on the metasedimentary rocks and dip at the syncline outlines. In contrast, a much steeper overall slope angle that can reach up to the maximum single bench angle would be possible in the north, if leaving a safety pillar of stronger pyroxenite in the slope wall to prevent sliding in the thick Alluvial cover sediments. Based on the findings the mining plan was developed, which included as main tasks the selection of the most suitable mining concept, a pit optimization analysis, mine layout design, mine sequencing, long-term production scheduling, and mine equipment selection.

Early determination of jumbo drill performance is crucial for selecting appropriate mining and civil engineering equipment. Quick and simple laboratory tests are needed for accurate predic-tions of on-site drilling rates. The Sievers’ J-miniature drill test represents thrust and rotation in a rotary-percussive drilling process. Continuous monitoring of drill penetration in these tests provides valuable information on penetration rate–time plots. In our study on sandstones and limestones from an Asturias mining site, miniature drill tests reveal two distinct periods in pen-etration–time curves: an initial period with a peak attributed to drill bit adjustment and a subse-quent stable period, offering a realistic representation of material drillability. Comparing labor-atory test results with jumbo drill performance in the same lithologies opens a new possibility to predict jumbo drill performance.

Úcar's criterion establishes a correlation between the principal stress axes during failure and the compressive uniaxial strength as well as the tensile strength of the rock. Consequently, it can be employed in the "prediction mode" during the initial stages of a project to determine the parameters for the resistance equations using simple compression and tensile tests (such as Direct Tensile or Brazilian tests), yielding a reliable estimate (with a confidence level of over XX%). As the project progresses to more advanced stages, it is generally recommended to conduct triaxial tests on specific rock units. In such cases, Úcar's criterion demonstrates a remarkably accurate fit. This study explores both aspects of Úcar's criterion, utilizing literary and experimental triaxial test datasets (over one hundred independent data sets, covering a wide variety of rock types) to evaluate the level of data fitting achieved. Furthermore, a similar analysis is conducted using the Hoek-Brown criterion, allowing for a comparative assessment of the performance of both criteria. From the analysis of the results it can be seen that the Úcar's criterion, used to predict the rock behaviour (i.e. with uniaxial tests and stresses), compares favourably even with the use of the H-B equations in adjustment mode (i.e. with triaxial tests).

This research studied the size effect and anisotropy of shale strength under polyaxial compressive stress conditions through laboratory experiments. Firstly, this research designed an in-house polyaxial compression test setup, which included a uniaxial compression test machine, biaxial platens, and confining devices. Secondly, this research prepared cubic shale specimens at the sizes of 25.4, 50.8, and 76.2 mm and orientations of 0, 45, and 90°. At last, this research conducted the uniaxial, biaxial, and triaxial compression tests on these specimens. The test results shows that the strength presents a decreasing trend as size increased irrespective of specimen orientation and stress condition. The anisotropic behavior of strength is unaffected by specimen size, but it varies as the stress condition changed. This transition is due to the second principal stress, which has a noticeable effect on the failure mode of shale and leads to the change of strength anisotropy.

Permeability around faults varies locally due to the existence of damage zone and clayey fault cores that experienced deformation and fracturing. Therefore, proper assessment of local changes in permeability around fault is recognized as an important research area for geoengineering applications such as radioactive waste disposal and carbon sequestration and storage. We developed a simple permeability testing device to measure the distribution of hydraulic conductivity around faults. The key advantage of this equipment is its porta-bility and simplicity, allowing on-site measurements. First, we used this equipment to measure the hydraulic conductivity on the standard rock samples and compared the results with data obtained from conventional laboratory hydraulic conductivity tests. Thereafter, we applied this approach to rocks containing faults to study the characteristics of hydraulic conductivity around faults.

Coastal protection structures are often constructed from locally quarried rock, and are subject to harsh service conditions throughout long service lives. Durability of the rock is essential. By means of a thorough review of engineering standards and similar documents we show that petrological properties are known to be key controls on durability, but seldom feature in design guides. We surmise this is due to the use of subjective petrographic assessments. A review of the wider geological literature shows that quantitative methods are commonplace in petrology, but have not been adopted in rock engineering. We report on recent research work from Iran which shows that durability can be accurately predicted by applying machine learning methods to customary rock mechanics properties, and we suggest that combining these approaches with quantitative petrological data will allow improved design of coastal protection structures.

Open-ended (OE) pile field tests performed in low density chalk have demonstrated a unique installation response not widely observed in other geomaterials. This has encouraged the development of new CPT based design methods (ICP-18). Recently, A campaign of small-scale pile and CPT tests on intact soft rock materials, has been undertaken using a new multi-axis loading frame offering new observations on this unique behaviour. Similarities in model and field scale numerical tests suggest that the effects of stress-state may be less marked in the case of structured materials. Although scaling and stiffness issues certainly exist, the performance of the ICP method is trialled at small-scale enabling a new discussion on the applicability of small-scale pile tests in rock, scaling aspects and the changes intact rock fabric under-goes during subject to pile insertion which are revealed using X-ray tomography.

Mechanized tunnelling is the most used construction method for long tunnels due to its high excavation speed and enhanced worker safety. For deep tunnels, the study of the interaction between the ground and the supports is essential for the structural design of both shield and segmental lining which may be subject to heavy loads. For such scenarios, it is crucial also to assess the risk of entrapment of the Tunnel Boring Machine (TBM). Despite the three-dimensional nature of the problem, full axial-symmetric or 3D numerical calculations are rarely employed in the design practice because are time-consuming and demand advanced numerical skills. A recent paper proposed a simple and effective numerical procedure based on full axial-symmetric analyses. The procedure is described and validated by comparing the results of a case study with reliable data reported in the literature, obtained through 3D advanced numerical approaches that explicitly simulate the radial gap closure.

The current paper deals with geotechnical challenges and tunnelling experience gained during the detailed design phase of new tunnels in the frame of the Sotra Link Project (SLP) in West Norway. It consists of several civil works between Bergen and Øygarden, along the existing Riksveg 555: 4 main road tunnels (Kolltveit, Straume, Knarrvika, Drotningsvik), 3 pedestrian and bicycle tunnels, 19 road and pedestrian underpasses, 23 tunnel portals, 22 bridges and viaducts, 14 kilometres of pedestrian and bicycle paths and 24 kilometres of two-lane access. Geotechnical complexities analysed in this work are mainly related to the design of technical solutions for rock support under the following conditions: i) low overburden with loose shallow deposits and interference with existing and new nearby structures, ii) metric fault zone extension with expected swelling potential. Starting from a preliminary solution based on the NGI Q-system, the detailed design overcomes these challenges throughout finite element numerical analyses. This approach leads to a suitable dimensioning of customized linings and specific tunnel face support, together with partial excavation phasing when required. Within this context, two significant case studies are discussed with reference to Drotningsvik main tunnels: the first one concerns the design of the sections close to Kiple Lake (Kiplevatnet), where partial front reinforcement and surface grouting are foreseen. The latter case deals with a fault zone crossing located 500 meters western, by adopting a full front reinforcement and partial excavation phasing. The observational method supported by an extensive monitoring campaign during the construction phase will allow for possible design optimisations based on properly back-analyses. Currently, the delivery tasks for Sotra Link project are in line with the contractual scheduling. The project contract was awarded in September 2021 for a total value of 1.25 billion € and the design phase is expected to finish in 2024, while the infrastructure will be opened to traffic in 2027.

Ornamental rocks are competent rocks that are usually arranged in layers of dozen meters of thickness. These form rock masses, affected by joints and fractures of tectonic origin and very extensive stratification planes. Thus, fractures and faults with extensions around hundred meters often cause important instabilities in mining operations. When blocks with tens of thousands of tons appear, their stability must be evaluated and, if it would be necessary, controlled. There are several known cases of plane failures involving large blocks of rock in limestone and marble quarries. Stability 2D analysis, such as the one developed by the limit equilibrium method of Hoek and Bray (1981), face certain difficulties. It makes sense, that block geometry is variable depending on the sections that we set, besides, this is just one of the differences considered among those chosen sections. In fact, a posteriori study of these instabilities would show, important lateral differences in the resistant conditions of the failure planes that drive to sliding. Moreover, the loading conditions induced, by blasting or by water inflows, are not equal in every single section. Taking advantage of the strength of these large potentially movable blocks, considered as a set of sections, it is possible to transfer the force requirements among them to compensate the lack of resistance of some specific sections with extra of the surrounding ones. So we provide, as an example, the back analysis of a large 40,000 t sliding marble block. Then we have divided a 40 m high and 60 m. wide block into 10 meters slices, to evaluate the whole equilibrium so we can explain the sequence of ruptures that led to its collapse.

Normally, two in situ methods are used to assess the rock at-rest earth pressure coefficient (k0): one is the Hydraulic fracturing method that obtains in-situ stress average over a sample of a few square meters, and the other one is the Overcoring techniques that measures in-situ stress average over grain size areas. This paper analyses a total of 17 hydraulic and 51 overcoring successful tests into the Sandstone rock. The parameter k0 has a big influence on the structures constructed into the rock. In this analysis is presented a secant pile wall with piles of diameter 0.75 m separated 1.8 m embedded into the Shale and Sandstone rock. At the beginning the movements predicted by 2D numerical model were ten times greater than the movements observed in the inclinometers during the excavation. Thus, in this study was found out that this large difference of the movement is due to the larger k0 coefficient. Next, the k0 coefficients were corrected so that the movements predicted by the numerical model match with those measured. The calibration of the k0 coefficient was up two times the empirical Jaky’s k0 coefficient. This calibration had influence reducing the resulting forces of the wall during the excavation phases. Finally, the k0 results from the in situ tests and the calibration values were compared, showing that both results concur for the k0 lower bound of the test results.

Material heterogeneity and shear strength variability are the main stability analysis considerations for the interbedded sedimentary rock slope due to interlayer slip potential. In this study, an interbedded sedimentary rock slope located in Terengganu, Malaysia, was examined. The composite stratified geostructure was projected for 2D surface morphology using point cloud photogrammetry, thus plane segmentation for dip measurement. The inter-bedded rock slope was modeled explicitly, where the location of rock beddings and potential weak layer materials are well defined. The limit equilibrium analysis for factors of safety determination was extended with sensitivity and probabilistic analyses for a wider range of failure potential factors. The validation using finite element analysis significantly justified the stability analysis result based on the shear strain behavior.

Reliable prediction of excavation impacts on surrounding rock mass is one of the crucial sub-ject in rock engineering. In this paper, the impacts of new tunnel construction intersecting an old tunnel is studied using the numerical modeling for case study of the Tehran-Shomal free-way project. The numerical modeling is performed by utilizing FLAC to evaluate the induced displacement and damaged zones surrounding the tunnel as a function of horizontal to vertical stress ratio (k). The results indicate that, both horizontal and vertical displacements induced by excavation and also the plastic zone show asymmetric spatial distribution around the tunnels due to the especial shape of tunnels intersection. The increase of k ration shows direct and re-verse effect on the horizontal and vertical displacement, respectively. In addition, by increasing the k ratio, the total displacement of observation points increases and the mechanism of yield-ing of surrounding rock is converted from shear to tension

This paper focuses on a case study of the use of numerical modelling to assess the influence of in-situ stresses and rock mass mechanical properties on the behaviour of a sill pillar in an underground metal mine. The loading conditions on the pillar are a result of a multiple panel, bottom-up advancing open stoping mining sequence with cemented paste fill. The sill pillar is exposed to increased induced horizontal stresses, which could result in rock mass damage or depending on the rock mass strength and geometry of the pillar. In extreme cases, the pillar may collapse, leading to ore loss or compromised worker safety. The numeri-cal modelling analysis in the case study was used to predict the rock mass deformation as af-fected by the mining sequence, in situ and induced stress conditions, and rock mass and paste fill properties to assess the pillar stability from stress-related damage.

Piezometers are instruments that can produce high-quality information if suitable installation and monitoring procedures are followed. Attention must be paid when prescribing the type of piezometer and the installation procedure in order to minimize errors and optimise the quality of the obtained information. The use of piezometers as geotechnical instruments is a commodity. However, attention needs to be paid to the installation procedure as highlighted in the ISO/EN18674 standards. The aim of the paper is to exemplify how the use of piezometers can be optimized and how the most standard errors can be avoided.

Mining and geomechanical conditions during mining operation in underground mine are changing all the time. The changes depend on many factors, as e.g.: the buried depth, type of rocks, geomechanical parameters of rocks, the size of mining face, the type of exploitation system or the space layout of mining in a field. However, as the result, all these factors influence on the state of stress. They determine the value of abundant stress and the direction of principal stresses. What is interesting, there is not only change in the primary stress next to the exploitation panel, but the rotation of the principal stresses as well. This fact is very often omit, because it’s impossible to solve this problem analytically. One can only assess it using numerical methods or carrying out expensive and time consuming rock mass monitoring underground in a mine. Employing numerical calculations the state of stress around the roadway is often determined in 2D models, which cannot show the stress rotation. This information can be found only using 3D models. However, the most valuable results can be received with the help of in situ measurements, which can be carried out with some biaxial or triaxial stress meters. The paper presents the results of underground monitoring and numerical analyses of state of stress in the rock mass during longwall panel advance in a coal underground mine. The in situ stress measurements were conducted with the help of biaxial stressmeters with vibrating wire installed in the coal ribs of a maingate, approx. 10 m deep in a non-fractured rock. The measurement data were registered automatically every 6 hours. This data allow to calculate not only the value of major and minor stresses but also changes of the angle of a major stress. The results of stress monitoring, together with the results of geomechanical parametrs of rocks done in the laboratory, were the base for 3D numerical modelling. Thanks to modelling the rule of principal stress rotation were shown. Conclusions are of a crucial importance for planning mining operations. The knowledge about the stress regime and its possible change can help in support system design for gates and improve the staff safety.

Ryukyu Islands constitute the south-west part of the Japanese archipelago. The age of the basement is pre-Cenozoic and the basement rocks are chert and schists. Cenozoic sandstone, shale and limestone overlay the basement rocks. These rock units are followed by Tertiary Shimajiri formation and all formations are covered by Quaternary Ryukyu limestone and Holocene deposits. The geo-engineering issues are mainly associated with the Shimajiri formation and Ryukyu Limestone. Particularly, landslides and stability issues of open or underground excavations in Shimajiri formation are major geo-engineering problems. It is well known that mudstone of the Shimajiri formation are subjected to degradation due to cyclic wetting and drying in relation to the water content variation. They also have time-dependent characteristics. The intact mudstone has uniaxial compressive strength (UCS) ranging between 0.6-3.6 MPa under natural water content conditions. Particularly, younger mudstone belonging to Shinzato Formation has lower UCS while older mudstone belonging to Yonabaru Formation has higher UCS. When mudstone layers are exposed to atmospheric conditions they absorb or desorb water and they exhibit volumetric swelling or shrinkage. This interaction with water causes their degradation and the physico-mechanical properties become a function of water content. The authors have been involved with a project where the mudstone layers belonging to Shinzato Formation and having some small normal faults caused some instability problems during a construction of a deep open-cut waste storage facility as a result of groundwater level changes during a heavy rainy period. New horizontal borings were done and cores from these borings utilized for tests on uniaxial compressive strength and Brazilian tests under different water content. The experimental studies involved the evaluation of physico-mechanical properties as a function of water content. Furthermore, groundwater diffusion characteristics of mudstone and related volumetric changes are experimentally investigated. During experiments, it is observed that some samples failed along some existing structural weakness planes. A multi-parameter monitoring system was installed and measurements were carried out for almost one-year. On the basis of these studies, some limit equilibrium analyses on the stability of the open-cut excavation and discrete finite element analyses (DFEM) on its measured deformation response were carried out. The outcomes of this integrated study involving various experiments, monitoring and numerical analyses are presented and their implications in practice are discussed.

The conventional design approach of any type of passive protection work aiming at reducing the risk associated with rockfall is energy-based: the total kinetic energy of the falling block in a given position of its trajectory (action, in Limit State Design (LSD) terminology) must be compared to the maximum energy absorption capacity of the protection work (resistance, in LSD terminology). The LSD approach, implemented in Eurocode 7 (EC7), shows some limitations in the case of unconventional geotechnical problems such as rockfall phenomena, since the main parameters of these systems are not considered. To overcome these limitations, one proposed solution is the application of Reliability Based Design (RBD) approaches through the definition of a reliability index, a useful and complementary tool to provide geotechnical structures with a uniform probability of failure. The RBD approach deals with the relationship between the loads that a system must support and the system's ability to support those loads. The RBD therefore shifts the analysis towards a fully probabilistic one, in which each parameter is considered a variable expressed by a known Probability Density Function (PDF). In this work, attention has been given to innovative rockfall protection structures such as hybrid barriers and/or attenuators: they do not stop the block by capturing and retaining it in a deformable net, but by dissipating its kinetic energy (up to 0 for hybrid barrier) and forcing it along a trajectory close to the ground or guiding it towards a collecting area. Therefore, in ideal conditions, the block does not stop within the net itself. Considering the applicability of a RDB approach, the paper will focus on the description of the rockfall phenomenon, namely the action on the hybrid barrier/attenuator. To describe the process of a moving block impacting it, two main parameters are identified: the Total Kinetic Energy (E_k) and the position of the impact location with regard to the structure. Assuming a 2D simplification of the problem, the second parameter corresponds to the height of bounces (H) in a given position along a slope. This works shows how, by employing a robust statistical approach and a suitably large set of numerical simulations, it is possible to define the Cumulative Distribution Functions (CDFs) of these parameters. From these two curves, it is possible to identify, through the use of proper statistical tests, the best-fitting PDFs and, therefore, use them as input for a probabilistic design approach such as RBD.

El Caminito del Rey, a renowned hiking trail located in the province of Malaga, Spain, is not only celebrated for its breathtaking beauty, but also for its notable susceptibility to rockfalls. The trail traverses a rugged terrain characterized by towering cliffs comprised of various rock formations, including limestone and conglomerate. The structural integrity of these rocks is gradually compromised over time due to weathering processes such as freeze-thaw cycles and erosion. When coupled with the influences of gravity, vibrations arising from human and wildlife activity, as well as natural seismic events, the stability of the cliffs becomes compromised, resulting in frequent occurrences of rockfalls along the trail. Despite persistent efforts to mitigate these risks, such as regular inspections and the installation of protective barriers, the inherent geological nature of the gorge renders the complete prevention of rockfalls an intricate challenge. In light of these circumstances, this study aims to take the initial steps towards implementing an advanced safety system on El Caminito del Rey with regards to rockfall hazards. The primary component of this undertaking involves the development of a susceptibility model based on rockfall simulations. The process unfolds in three key stages. Firstly, a comprehensive virtual 3D model of El Caminito is generated. Secondly, ancillary data and meticulous characteristics of the rocks constituting the gorges are compiled and incorporated. Lastly, utilizing the aforementioned information, rockfall events are simulated. This abstract will expound upon the challenges surmounted during the course of the project, as well as provide an overview of the principal findings. Furthermore, the forthcoming research agenda for the area will be outlined, seeking invaluable feedback from the interested audience. This feedback will play a crucial role in guiding future research efforts in El Caminito, with the ultimate objective of enhancing the safety of the trail. While the allure of El Caminito del Rey's awe-inspiring scenery remains undeniable, the trail managers are diligently prioritizing visitor safety by proactively preparing for potential rockfall hazards. Through the implementation of an advanced safety system informed by the findings of this study, the aim is to strike a balance between preserving the enchanting experience offered by El Caminito and ensuring the well-being of its visitors.

The Aurunci and Riviera di Ulisse Regional Parks are known for their cultural landscape and related trails that, every year, are hiked by thousands of visitors. The “San Michele Arcangelo” historic trail is the most important trail of the Aurunci Regional Park (central Italy) and forms the cultural asset of the park. The trail is located along the southern slope of Mt. Altino, prone to rockfalls, and is hiked every year by thousands of faithfuls on pilgrimage who are exposed to such kind of instabilities. The trail of Punta Cetarola in the Riviera di Ulisse Regional Park is a significant example of coastal trail, corresponding to a segment of the ancient “Flacca” road and, similar to the “San Michele Arcangelo” historic trail, is developed along a slope prone to rockfalls. To contribute to a better understanding of the condition of development and evolution of rockfalls in these two areas, providing a susceptibility scenario able to support the adoption of mitigation measures, a specific analysis was completed on the basis of field and literature data. Photogrammetric reconstruction of accessible slope sectors and scan-line-based field outcropping analyses were completed to derive geomechanical features of rocks and estimate potential detaching block volume. Possible mechanisms of detachment were analyzed using the reduced complexity Markland test method. Susceptibility to rock block detachment, rockfall propagation and block deposition was analyzed using GIS processing and deterministic/probabilistic propagation analyses. In particular, adopting the Rockyfor3D software, results of slope analyses and simulations indicated: i) the potential for rock blocks detachment by wedge and planar sliding or toppling, ii) the localization at higher elevations over the whole study area of slope sectors susceptible to block detachment, iii) the moderate susceptibility to both propagation and deposition of rock blocks along the trail, iv) the control exerted by the hydrographic network on rockfall propagation, v) the control exerted by screes and slope angle on rockfall deposition.

Coastal communities face recurring erosion problems and flooding. It is complex to carry out a technical-economic balance, which allows for finding an effective solution. With increasing risks and associated management costs a congruent solution designed, which consists of the conformation of modules, composed of an exoskeleton of rhomboidal meshes of high yield strength (>1650MPa) stainless steel duplex, rock block fill, which can be executed in place or precast. This solution designed by gravity, in which the structure's weight plays an essential role, is efficient when faced with certain significant wave height and slope inclination conditions. For its design, in addition to the demands in energy and uplift terms, the abrasion generated in the components, the sediment dragging process that causes both the entry and exit of the water from its bracing, only the use of stainless steel as the only material, guarantees the effectiveness.

Coal Pillars are important structural elements in underground mining. Unstable pillars can result in collapse of roof and walls and even coal burst; hence its reliability analysis is of great importance. This paper presents a novel probabilistic framework to assess system reliability of section pillar. The variation of coal mass parameters, such as UCS, friction angle, cohesion and Young’s modulus, are considered. Two different failure modes, with respect to pillar stress and strain, are investigated to obtain reliability indices using FLAC3D, Stochastic response surface (SRSM) and First-order reliability method (FORM), then Bimodal bound and Linearization methods are adopted to compute system failure probability. Finally, coal mass parameters from a typical coal mine are employed and results suggest that both stress and strain limit states could have significant influence on the system reliability. The approach proposed in this paper could be a useful tool on the risk management of underground pillar.

Secured drapery systems with meshes have been used for years to stabilize the surface material in slopes and ensure the safety in different infrastructures. Historically, one of the first materials used as a mesh was double-twisted mesh. Over time, the need for materials with higher performanc-es arose, leading to the installation of steel cables or rope panels over the mesh, which was a slow and labor-intensive process. Furthermore, it is necessary to verify the use of meshes in the design, as geomechanical models are often complex and unrealistic. Key mechanical characteristics for de-sign are the tensile strength, punch resistance, and punch deformation. However, the transverse ten-sile strength is often overlooked, despite evidence showing its relevance. This article presents a re-liable numerical model calibrated using laboratory tests. It demonstrates the influence of transverse tensile strength on deformation and punch resistance, enabling the optimization of bolt design with-in secured drapery systems.

The Callovo-Oxfordian claystone (COx) is an anisotropic rock formation that serves as the host for the envisaged deep geological repository for intermediate-level and high-level long-lived radioactive wastes in France. In this context, the construction of several T-shaped gallery intersections is a common technique used for accessing the surrounding cells. In this work, a numerical analysis of a T-shaped gallery intersection excavation at great depth in the COx claystone is presented. A Drucker-Prager elastoplastic constitutive law with shear strength hardening is used to describe the rock matrix and the inherent anisotropy is implemented using the fabric tensor approach. Simulations include galleries with circular cross-sections intersecting at a normal angle. The focus lies on the mechanical characterization of the zone around the intersection. The results highlight the plastic strain distribution around the main gallery walls. Furthermore, the extension of the plastic zone is presented.

This paper proposes an analytical approach for analyzing rock slope stability based on a three-dimensional (3D) Hoek-Brown (HB) criterion to consider the effects of 3D stress and strength. The 3D HB criterion, considering an associate flow rule, is utilized to describe the perfectly-plastic behavior of rock mass under a plane strain condition. To reflect the change of friction angle on the failure surface, the potential failure surface (PFS) is divided into small segments with each segment being assigned a unique friction angle. The upper bound theorem of limit analysis is combined with the strength reduction method to determine the factor of safety (FOS) of a rock slope with a defined PFS. By optimizing the PFS, the minimum FOS and the critical failure surface (CFS) of the rock slope are obtained by the customized genetic algorithm. The proposed approach is validated by comparing it with an HB criterion-based solution and numerical simulations. Parametric studies are also performed to investigate the effects of rock mass properties, slope geometry, and loading conditions on the FOS and CFS. The results indicate that ignoring the 3D stress and strength of rock leads to underestimation of FOS and it is important to consider the various factors when evaluating the stability of a rock slope. For the effortless application of the proposed approach, a Python-based graphical-user-interface application is developed as a stand-alone executable app and is successfully applied to analyze a rock slope.

Dionyssos marble quarry is located 30 km from Athens and it is an important quarrying site in Greece. Apart from standard commercial purposes, it is also used for the restoration of the Parthenon as it is part of the same marble deposit that was used for the construction of Athenian Acropolis monuments in the 5^th century B.C. The Dionyssos marble is a fine-grained metamorphic marble exploited partly open-pit and partly underground. The modern times exploitation started in 1949. The increased demand for ornamental stones has led to intensive exploitation of the existing marble quarry. The gradual depletion of surface deposits is a direct consequence of this increase. For this reason, the company proceeded to exploit part of its deposit using underground methods, which have the added advantage of minimal environmental footprint. By applying the method of room and pillars, openings up to 15 meters wide are achieved, while the maximum height of the rooms is 30 m. In this research the future underground development is considered. It is envisaged at the higher level of the two existing underground openings and will consist of five rooms in the North-North-West direction excavated in six stages and two rooms in the North-North-East direction excavated in twelve stages. Support measures only include resin rockbolts of length adapted to pillar or roof installation. A set of advanced numerical simulations of the room and pillar gradual development and support is performed using a different numerical scheme for the evaluation of the stability; the distinct element method is used so as to include the effects of macro-discontinuities affecting the stability of the pillars during the top-to-bottom development of the marble extraction. Extensive laboratory tests have been performed on rock samples and the effect of scale on the peak compressive strength is also taken into consideration. The results of the analyses have shown that the stability of the exploitation is secured for the specific underground development.

The swelling of anhydritic rocks is responsible for severe damages to numerous tunnels. Alt-hough the first problematic cases were recorded more than a century ago, there are still knowledge gaps concerning the swelling behaviour of anhydrite, which introduce uncertainties in tunnel design. A major uncertainty relates to the magnitude of the developed strains due to the anhydrite to gypsum transformation, which depends inter alia on how gypsum crystals will grow. The latter may be influenced by the porosity, specifically whether the new crystals will grow within the available pore space or push the particles apart causing expansion. This paper investigates this effect by means of experimental tests conducted on artificial specimens of an-hydrite and kaolin powders. It is shown that, ceteris paribus, the strain developing during the anhydrite to gypsum transformation decreases with increasing initial porosity. The presented experimental results are valuable for better understanding of the observed phenomena.

The unloading disturbance during the excavation process in rock masses can significantly affect the safety of deep underground structures, especially when encountering rock frac-tures. In this study, the unloading process of normal stress was conducted using three dif-ferent levels of unloading rates. Simultaneously, the acoustic emission (AE) technique was employed to monitor the growth of microcracks at the interface. The recorded AE count, AE energy and calculated AE b-values were compared with the evolution of stress and displacement to confirm the correlation between AE signals and unloading behaviour. The experimental results revealed that the stress state associated with a low unloading rate is closer to the failure envelope compared to high unloading rates. During the unloading pro-cess, the maximum AE count, the highest AE energy, and the sudden decrease in b-value can serve as indicators that facilitate short-term prediction of failure sliding.

Explosive-free rock breakage methods have been the subject of increasing research in the past three decades as they are considered more environmentally friendly than traditional rock fragmentation with explosive energy. This paper summarizes the results of research findings on rock breakage with expansive cement, also known, soundless chemical demolition agents. Expansive cement is a powdery material that expands upon curing in a borehole causing it to eventually fracture. Expansive cement is a commercially available product that is usually used in the construction industry for the demolition of concrete foundations. Only in recent years that interest in the use of expansive for mining applications has been on the rise. Some of the challenges faced with the use of expansive cement are 1) rock is considerably stronger and stiffer than concrete, 2) rock is subjected to confinement in-situ, and this would inhibit the breakage mechanism by limiting the expansion, and 3) expansive cement does not work well in cold climate conditions, which are frequently encountered in Canadian surface mines. This paper summarizes the results of experimental and numerical studies conducted to estimate the peak expansive pressure and its variation with host medium stiffness. Direct pressure measurement is used to validate the classical analytical method employed for pressure estimate using instrumented thick-walled steel cylinders of different expansive cement borehole diameters and wall thicknesses. A series of rock slabs from Stanstead granite is then tested with a central hole injected with expansive cement and subjected to uniaxial compressive stress of 5 MPa. The results are compared with those obtained from unloaded rock slabs. Expansive cement breakage performance is measured by the time of first fracture (TFC) and the minimum demolition time (MDT). Another series of tests examined the potential benefits in terms of TFC and MDT of a relief hole (empty hole) in the vicinity of the injected hole under uniaxial pressure. Finally, an Extended Finite Element (XFEM) of the granite slab with expansive cement borehole is built with Abaqus software to help estimate the appropriate spacing between EC holes to achieve fragmentation. The results are used as design guidelines for rock fragmentation of boulders and uniaxially loaded pillars in the field.

In the Montserrat Massif (in Catalonia, NE of Spain) a common mechanism of rockfall generation is the differential erosion of thin weak layers, composed by fine-grained rocks commonly described as lutites or mudstones, interleaved within the conglomeratic rock mass which shows a long-term durability. Both materials are terrigenous and detrital clastic rocks, formed in an alluvial fan delta during the Eocene epoch, and exhibit very different behavior against weathering. This difference is explored in the laboratory through durability tests, before and after being subjected to freeze-thaw and wetting and drying ageing tests, and then correlated with theirs textural and mineralogical properties. The findings allow to explain the morphologies and detaching mechanisms observed in the field. The laboratory tests performed are X-ray mineralogical analysis, petrographic analysis of thin sheet samples, simple compression with strain gauges, Brasilian indirect tensile strength, Slake durability, and ageing by freeze-thaw and wet-dry cycles. Five different detrital textures from conglomerate to fine sandstone with muddy matrix (wackestones) have been identified and grouped into two main geotechnical units related to rockfall dynamics. On the one hand, the rock blocks of conglomerate and coarse sandstone susceptible to fall; on the other hand, the weak levels producing under digging of the previous ones formed by fine-sandy wackes and muddy wackes. Despite geomechanical similarities in intact conditions, they differ clearly once weathering cycles are applied by humidity and temperature. Thermal weathering is found as very relevant when explaining the rockfall preparation mechanism leading to toppling. A synoptic model of this mechanism is drawn accordingly. Different influencing factors on the rock block stability are analyzed. Thanks to the monitoring of the rock mass carried out in Montserrat, representative examples of the flexure-toppling mechanism on rock blocks and needles are found. The annual thermal cyclic behavior is shown as composed by elastic and plastic components that evidence the weakening of the base.

In recent years, the historic centre of Florence, enlisted as a UNESCO World Heritage site, has experienced several incidents where fragments have detached from the structural or decorative elements of its historical buildings. Notable examples include the detachment at the Basilica di Santa Croce in 2017 (which led to the death of a Spanish tourist) and the ones at Palazzo Corsini in 2018, at Palazzo Ginori Conti in 2019, and at Palazzo Pucci Sansedoni in 2020. The detachment phenomenon is a common issue in urban areas where stone materials are used in historical constructions; Florence`s stone-built heritage, however, presents unique characteristics that amplify the risk of significant detachments. Specifically, the types of sandstone used in Florentine historical constructions, known as "Pietraforte" and "Pietra Serena," contribute to the increased risk of sudden collapses due to specific attributes that make them susceptible to detachment and structural instability over time. For example, convolute laminations and calcite veins, typical macroscopic characteristics of Pietraforte, often represent critical discontinuities in an otherwise compact matrix. Currently, the detachments issue has been managed through continuous monitoring and periodic removal of loose and instable material. However, this approach is not cost nor time effective and fails to provide a sustainable long-term solution for both the preservation of UNESCO World Heritage List monuments and the safety of visitors. The existing safety regulations and protocols do not offer specific guidelines for interpreting and addressing these detachment phenomena, so the personnel in charge of emergency safety interventions must rely on empirical assessments, lacking comprehensive recommendations for dealing with the complexities of these natural and variable materials. To better understand and address this problem, a new approach is therefore needed and its foundations are presented in this study. To address the lack of specific risk assessment methods for these unique facades within existing protocols, we propose the adoption of a rock mechanics perspective to adequately account for the diverse lithologies and their variable mechanical behaviour. By utilizing tools from slope stability and rock mass analysis, such as intact rock characterization via NDT (Non-Destructive Testing) surveys and discontinuity characterization trough geomechanical survey and Point Clouds analysis, we aim to define risk parameters that are more suitable for these particular structures, establishing the operational framework for a diagnostic protocol that aids decision makers to better direct and assess the need for conservative and safety interventions.

The depletion of mineral reserves has led to deeper underground mining which comes with challenges such as rockbursts, large deformations, and inaccurate dilution estimations. Therefore, stope stability remains a significant safety factor in underground deep mining. In fact, assessing the stability of stopes is essential to better predict instabilities and sloughing around the excavations. This study compares the stability analysis of open stopes using stability graphs and numerical modelling, to evaluate the effect of different variables on the stability of excavations. The study concludes that using stability graphs alone does not suffice to determine stope stability; numerical modeling is also essential to complement the findings. Additionally, the stability analysis of a stope in a 1000 m deep mine will differ from a stope in a 2000 m deep mine, with similar geometry and geological conditions. In conclusion, using the stability graphs in deeper mines may underestimate the stability of the stope.

Stable slope performance is a crucial aspect in the early stage of pit commencement to achieve the plan of ore extraction during the operational phase immediately after complet-ing the feasibility study. Understanding of geotechnical conditions increases with the ex-posure of the excavated slope during pit development. A reliable slope parameter shall be proven once the proposed geometry is correctly applied, resulting in a stable slope. How-ever, on some occasions, unforeseen risks may arise due to limited geotechnical infor-mation during the feasibility study. This paper discusses the efforts performed at the Bozshakol copper mine in the early stages of pit development, including the establishment of geotechnical programs, implementation of control measures for early instability concerns, addressing groundwater issues, interacting with the mine plan for design adjustment processes, and eventually optimizing pit design throughout the development stages.

ABSTRACT: Hydraulic erosion occurring at dam spillways can be critical for the dam struc-ture. Current assessment methods rely on empirical correlations between water erosive force and rock mass resistance, yet they stem from limited data, affecting their accuracy. This problem is addressed by using a laboratory-scale physical model simulating spillway condition. This model assesses various rock mass parameters, including water pressure, joint characteristics, and block size. By modifying concrete block arrangements, different geomechanical conditions are repre-sented, allowing pressure evaluation. Key parameters like joint opening and orientation, and block shear strength are studied in various conditions. The model's test section, equipped with pressure sensors, facilitates an analysis of hydraulic erosion processes, enhancing our understanding of spillway rock mass erosion dynamics. This innovative model promises a better evaluation of hy-draulic erosion's complexities, a crucial aspect of effective spillway design and maintenance.

Hoek-Brown failure criterion is one of the most widely used failure criterion for rocks in the world. For its use, the mi empirical parameter for a specific rock type is needed. To determine the mi constant, a triaxial test is recommended, which gives a linear relationship s1-s3. How-ever, the full stress path for every rock starts with uniaxial tension and this gives a nonlinear envelope. 55 series of tests are carried out for 4 rock types: sandstone, claystone, limestone and conglomerate - to show what is the difference between the results of the mi determina-tion, using two different approaches. The analysis of the results shows that the consistency with the regression models developed by researchers is higher if using the second set of re-sults – with average tensile strength. So this approach allows to determine the mi parameter more precisely for every tested type of rock.

The characterization of the thermal properties of crushed rock samples is not experimentally straightforward. In the case of thermal conductivity, some authors estimate this property based on solid rock plugs (e.g. optical thermal scanning, split bar, line heat source) what is not a convenient approach for granular materials with variable grain sizes. On the other hand, the determination of the specific heat of rock samples is typically based on enthalpy balances (e.g. differential scanning calorimetry, DSC) by achieving thermal equilibrium between the hot sample immersed in a reference fluid at a constant temperature. However, such techniques require small-volume comminuted samples if the grain size of the rock forming minerals is significant. All of the previous methods require, in addition, precise information on the physical (grain density, porosity, etc.) and mineralogical properties of the materials tested. To cope with these problems, the preferred approach of some researchers when dealing with granular materials is to assess thermal conductivity by estimating its heat capacity based on cylindrically-packed volumes and then applying to the bulk a radial heat source and simultaneously measuring temperature in selected locations along the diameter of the cylinder. Then, the measured thermal conductivity is an average conductivity of the packed porous sample (i.e. a combination air-filled porosity and the solid grain skeleton). This contribution presents the experimental methodology applied to assess thermal properties in aggregate rock packs as well as the analysis of the results of several tests carried out with basaltic aggregates intended for thermal energy storage.

Understanding the structure of the porous network in chalk is essential for many fields such as unconventional reservoirs, geothermal energy, CO₂ storage, or engineering. First, the study described qualitatively and quantitatively the properties of the porous network of chalk, a major component of the upper crust of Champagne-Ardenne. The chalk studied comes from the Grand Mont quarries (Saint-Germain-la-Ville, France). The study utilized various techniques including water porosity, mercury injection porosity, capillary water uptake tests, P- and S-waves propagation velocities, and scanning electron microscopy. Non-destructive and high-resolution 3D imaging methods such as X-ray microtomography and nuclear magnetic resonance were employed to determine pore geometry. Secondly, chalk was studied to understand its behavior during fluid circulation experiments at contrasting temperatures (cold rock - hot water // hot rock - cold water). A set of 130 samples was tested in 4 devices in order to produce a circulation of fluids: i) 150 cycles of water uptake by capillarity were carried out on chalks heated to 80 °C or at room temperature, with water at 8 °C or at 80 °C; ii) 150 thermal shock damage tests were obtained by quenching the samples at 80 °C in water at 0 °C; iii) a continuous transfer of water (10 L) at 80 °C or at room temperature was carried out by means of a device using the call of air exerted by desiccators placed under vacuum; iv) 10 L in chemical equilibrium with chalk circulated in control samples (without thermal stress) thanks to the design of a constant charge permeameter. The results showed that the water weakening phenomena in the chalk are not irreversible and that the temperature variations did not significantly affect the porous network or cause internal damage. However, the circulation of cold water in chalk preheated to 80 °C led to a reduction in water connectivity, due to the recrystallization of calcium and carbonate ions saturating the fluid and to the thermal expansion of calcite grains during cyclic heating phases. On the other hand, this recrystallization did not necessarily lead to a reduction in the volume of the pores. For experiments involving continuous circulation, the water connectivity has been further reduced. The uninterrupted flow of fluids increased the chances of a grain detaching from its position and entering a pore, thereby rearranging the pore space.

Time-dependent effects play a significant role, accounting for up to 70% of total deformations in tunnels (Sulem et al. 1987) [Int J Rock Mech Min Sci Geomech Abstr 24(3): 145–154]. The focus of this study is to determine whether the information from convergence measurements in a tunnel section can be used to identify specific constitutive law parameters describing both the short-term and long-term behaviour of the ground. Due to scale effect, actual in-situ mechanical parameters may differ from laboratory test results. Thus, the main objective is to directly calibrate constitutive law parameters, such as elasto-plastic or elasto-visco-plastic, from in-situ convergence measurements. A fractional constitutive law, for which an analytical solution is available for the stress and displacement field around the tunnel, has been chosen to model the behaviour of the ground. The use of fractional models is motivated by their ability to capture the time-dependent response of the ground with a good accuracy. Compared to classical constitutive laws, fractional laws enable to better describe the creep behaviour of the rock mass with a number of parameters that is significantly reduced (e.g., Caputo and Mainardi, 1971 [Pure Appl. Geophys. 91: 134–147]; Bagley and Torvik, 1983 [AIAA J, 21: 741–748]). This problem is framed as an optimization search, aiming at minimizing the squared error between convergence data points and the constitutive model predictions. Two approaches are combined to assess tunnel wall deformation: one empirical and one constitutive. The empirical convergence law (Sulem et al. (1987) [Int J Rock Mech Min Sci Geomech Abstr 24(3): 145–154] enables the extrapolation of convergences to long-term scenarios, serving as the basis for the optimization process subsequently applied to a specific constitutive law. The proposed method permits to characterize both the short-and long-term ground behaviour which can ultimately improve tunnel design. The method provides a means of calibrating constitutive parameters for implementation in numerical models and of assessing the long-term ground-lining interaction.

Solar energy installations are a prominent renewable energy source, requiring robust foundation systems to ensure their structural stability, cost-effectiveness, and long-term performance. This study presents a comprehensive assessment of the lateral load resistance of short socket piles for solar plant foundations in Bosnia and Herzegovina through experimental testing and numerical analysis. The experimental investigation was conducted to obtain data on the lateral load performance of the reinforced concrete bored piles. A total of 3 piles with a diameter of 40 cm and a length of 120 and 150 cm were installed for testing purposes. The pile socket depth, reached by the percussion drilling technique in dolomitic limestones, ranged from 20 to 50 cm, with the remaining upper portion of the piles being within clayey debris soil or highly fractured rock mass. Horizontal loading was incrementally applied at a point 20 cm above the ground surface, according to the procedure of the Quick load test outlined in ASTM D3966 – 07. The piles were tested until relatively large displacements were observed, ranging from 2.5% to 10% of the pile diameter, and unloaded to record the irreversible displacements. The test results indicate a notable increase in lateral pile displacement after reaching pile cap displacements ranging from 1% to 2.5% of the pile diameter, providing valuable empirical data for validation and calibration. To complement the experimental findings and gain deeper insights into pile behavior, a 3D numerical back-analysis approach was applied. The analysis included the nonlinear behavior of solid pile and rock mass elements supported by a discrete reinforcement embedded beam model. Good agreement between the model and measured data was obtained, indicating that the pile-rock mass system failed primarily due to reduced pile stiffness related to concrete cracking. Back-analysis results generally helped refine the understanding of pile-soil interaction mechanism, load distribution, and deformation patterns, enhancing the accuracy of predictions and design recommendations.

Coal mining presents several geotechnical challenges around the world. Limitations including data uncertainty and geological anomalies, coupled with risk acceptance in the form of “controlled” bench and inter-ramp scale slope failures in industry guidelines make slope collapsing an unavoidable and foreseeable aspect of economic rock slope designs in the mining industry. Technological advancements, such as three-dimensional slope stability modeling and ground-based interferometric synthetic aperture radar monitoring, in conjunction with traditional site investigation techniques such as drill core logging and face mapping, and remote sensing including photogrammetry and laser scanning, have proven to be successful in improving slope failure risk management. Improvements have included reducing personnel exposure to slope failure risks and earlier detection of emerging hazards which enable better remediation planning. This paper presents two case studies from coal mines in Colombia and Australia involving multi-bench, semi-ductile failures that were successfully managed using slope monitoring and response protocols. The data collected was utilized to improve geotechnical understanding enabling a more reliable forecast of future slope design risks and control measures to mitigate them.

In-situ stress knowledge involves the entire process of enhanced geothermal system (EGS) development, such as borehole stability, hydraulic fracturing propagation patterns, and mitigation of induced seismic risk. To eliminate the influence of high temperature, we employ the Anelastic Strain Recovery (ASR) technique for in-situ stress measurements in geothermal boreholes. ASR is a rock-core-based three-dimensional stress measurement method. Using the ASR method, we successfully measured the magnitude of in-situ stress at depths of 1500-4000m in China's first large-scale EGS site. To evaluate induced seismicity and fracture stimulation during EGS development, we simulated the variations in fracture slip tendency (Ts) near the injection well using the in-situ stress data. The results show that T_s is initially small, but as injection pressure increases to 46 MPa, the fractures reach a critical state (Tsmax=0.6), and further pressurization leads to gradual slipping of the fractures (Ts>0.6).

In France, abrupt collapse raises more problems of risk management than progressive subsidence. Thus, these two types of phenomenon need to be distinguished. Bases on Tincelin & Sinou (1962) principle, we have attempted to develop an easy-to-use methodology through the retro-analysis of the subsidence of part of the Vins-sur-Caramy mine in 1959. Works is based on a geotechnical analysis of a core drilling and mechanical laboratory tests. Method consist on the examination of two criteria a stability criterion (geometric criterion) and an overburden massiveness criterion (geological criterion). The geological criterion, more complex to understand, was examined using the deformation modulus (Em) of the overburden. This method provides an initial response to the case of the Vins sur Caramy mine. Further research will involve comparing this and other cases.

The present paper summarises the activities related to 3D rockfall hazard assessment in the zone of the heritage dam Matka near Skopje. The concrete arch dam is 29 meters high and it was constructed in the mid 30^ties of the 20^th century. It is the first ever built dam in Macedonia, is survived the infamous Skopje earthquake of 1963, and still working today at full capacity, after almost 90 years of operation. The wider zone around the dam and its lake are situated in the steep gorge of river Treska, characterized by pronounced rockfall hazard in general terms. The entire area is also known as a natural rarities site and attracts many tourists and rock climbers. In order to assess the rockfall hazard for the dam and its appurtenant structure (spillway) a 3D rockfall simulation was performed. In the first stage, the main challenge was to prepare a high-quality 3D model of the terrain and the dam. Several contemporary and innovative surveying techniques were combined in order to achieve this, explained briefly in the paper. Based on findings from engineering-geological mapping, old geological datasets, stereographic analysis, and defining seismic forces, local slope stability analyses were performed. Kinematic analyses confirmed the possibility for detachment of rockfalls, which is observed in reality, and not only in the exact zone of the dam profile. Next were defined the properties of the rockfall seeder zones. The shape, size, and weight of the possible rockfall blocks endangering the dam and the spillway structure were modeled. Due to uncertainties, both point and line types of seeders were applied. The software RocFall3D of the company Rocscience was used to perform the simulations. After running of the program, the paths of possible rockfalls were obtained and then analyzed. Results show that for the given position of the familiar rockfall zones, there is no direct hazard for the dam. The opposite was concluded for the spillway structure. Therefore, for this zone were performed additional analyses of the expected kinetic energy and the other dynamic components of the possible rockfalls. Possible protection types for the spillway were then discussed. The application of protection measures is obvious and subject to further design, however, many limitations can be expected due to the natural protected status of the entire area.

The doublet disastrous earthquakes occurred on February 6, 2023 in the south-east part of Türkiye. The first earthquake is named as The Pazarcık earthquake and occurred at 4:17 on February 6, 2023 and the second earthquake is named as Ekinözü (Elbistan) earthquake and occurred at 13:24 on the same day after about 9 hours. The first earthquake ruptured the segments of East Anadolu Fault (EAF) and Dead-Sea Fault. The Pazarcık earthquake was initiated at Narlı fault belonging the Deas Sea Fault System and involved the Pazarcık segment and Amanos segment belonging to East Anadolu Fault System, subsequently. The estimated total rupture length was about 250-270 km. The Ekinözü earthquake involved E-W trending Çardak fault with a total rupture length of 120-130 km. The magnitude of the Pazarcık earthquake has been estimated by different institutes and it ranged between 7.7 and 8.0 while the magnitude of the Ekinözü earthquake estimated by different institutes and they range between 7.6 and 7.7 (Aydan and Ulusay, 2023).

Several roadways and railway and underpass tunnels were damaged by the Pazarcık earthquake. In addition many rockfalls occurred at the portals of railway and roadway tunnels. The damage by faulting was quite severe at the railway tunnel near Ozan village and the offset was more than 200 cm. Another faulting induced damage occurred at an railway underpass tunnel at Kozdere and the relative slip was more than 30cm. The damage to concrete lining of the new Erkenek tunnels occurred at several places. Despite linings were reinforced, severe spalling and collapse were observed. DLI of the Erkenek tunnels ay be designated as 5 while it may be designated as 7 for the Ozan tunnel. These tunnels were excavated in weak rocks such as phyllite, serpantinized ophiolite and some slope mass movements were observed during excavation. The damage in the new Erkenek tunnels may be related to mass movements caused by heavy ground shaking. The old Erkenek tunnel was excavated in hard limestone and the damage was light although the tunnel was unsupported.

The Shaimdrone Project developed by Geoconsult, with the collaboration of the Polytechnical University of Madrid (UPM, Civil Engineering & Telecommunications Engineering), and financed by the Center for Technological Development and Innovation (CDTI), proposes a methodology for semi-automatic analysis, evaluation and management of massive geometrical data (3D point-cloud models, or 3DPC models) collected from rock slopes using drones. These technological advances increase the working safety of the technician who performs inspections on slopes at the roadside and reduces the impact on the road user due to temporary occupations. Both benefits optimize the duration of field work and increase the capacity and objectivity of risk analyses of the road slopes using and therefore of a better risk assessment.

From the R-SHRS (Rock and Soil Hazard Rating System) risk indexes for rock slopes (Geoconsult 2019, 2021) and the parameters that conform them, advances associated to Shaimdron allow the semi-automatic gathering of data, to compute geometrical parameters from the analysis of the 3DPC models, which are integrated in the R-SHRS_infra category. Similarly, the measurable aspects of the rock and soil masses that form the slopes are grouped in the category R-SHRS_geo, while the parameters that require historical records and frequency phenomena –hence being not measurable from point clouds– are groupted into R-SHRS_freq.

For the Shaimdrone Project, a methodology is developed to obtain data through drone flights, in which their flight operating parameters –distances, heights and flight speeds– are optimized for adequate data collection. Algorithms are also developed to obtain cross sections of the 3DPC models, and to identify lithoclases and joints. The identification of joints defining the rock mass structure of the study area has been carried out with advanced image processing techniques that reduce the noise associated to the irregularity of rock masses. The advanced data processing allows the user to compute aspects such as spacing, persistence, fracture rates (RQD), roughness, block volume, etc. Results obtained from the analysis of the 3DPC models, as well as from other complementary analyses, are integrated into a “risk reports application” that develops risk measures for a given road section, to be also stored in databases and integrated into GIS/BIM environments, for an adequate management of the information and to facilitate subsequent mitigation and investment plans to be conducted by the infrastructure manager.

Rockburst can be referred to the damage that occurs in rock excavations as a result of a seismic event that generates sufficient energy to cause violent failure of the rock mass. Rockburst events are known for their unpredictable and violent nature, representing a significant threat to workers’ safety, mining productivity, and operational costs. Therefore, a quantitative assessment of rockburst damage is significant for geotechnical risk management in seismically active underground mines. Over the past few decades, numerous studies have been conducted on predicting rockburst damage potential. Despite the scientific achievements and technological advances in ground control, rockburst damage still threating underground mine operations because of the elusive character of the rockburst phenomenon. This paper introduces a dimensionless index to quantify the rockburst damage hazard. Well-documented rockburst damage data compiled from an underground mine located in Canada and Australia were used to establish the index. The input data parameters include the capacity of the ground support system, stress conditions, presence of geological structure, excavation span, and peak particle velocity. The overall results showed that the predicted hazard level using the proposed index had good correlations with the actual rockburst damage scale. In addition, it was found that the most important parameters were the stress and support conditions. It was concluded that the results of this research could be used as a prediction tool to help engineers to adequately assess rockburst damage in seismically active mines.

The use of 3D slope stability models for assessing risk and opportunity across various time horizons from the life of mine, five-year (5YP), two-year (2YP) and quarterly or three-month (3MP) mine plans is becoming common practice. The goal is to improve mine design reliability, and as an industry, achieve digital twins for mining and slope stability. These improvements are facilitated by faster computing and user-friendly 3D slope stability software as well as in-creasing monitoring instrumentation deployment in open pit mines. This paper investigates the use of Hu coefficients for simulating pore pressures relative to pre-defined phreatic surfaces or groundwater tables to facilitate rapid updates to 3D slope stability models based on updated pore pressure data obtained from a network of vibrating wire piezometers (VWPs). It also dis-cusses pore pressure sensitivity checks for risk management, and the benefits and limitations of this approach.

In 2010 a process was started to stablish international standards on geotechnical instrumentation under the ISO umbrella. General concepts of these standards were published in 2015, the first part on extensometers in 2016, the inclinometers document in 2017, total pressure cells and piezometers were published in 2020 . All these documents have been published in English and French all over the world. In Europe these documents have been published under EN_ISO 18674. Part 8 on the use of load cells to measure load is in the last steps of the approval process and probably Will be published this 2023. The aim of the paper is to show the development and specific role of these standards on the use of geotechnical instrumentation.

The Mediterranean region has witnessed major infrastructure projects in recent decades, with multiple tunnels usually being constructed using NATM (New Austrian Tunneling Method). The essence of this method lies in continuous observation of deformations and geological assessment, allowing for optimization of the tunnel support system. However, the presence of BIM (Block-in-Matrix) rocks implies significant challenges to application of NATM. The BIM rock exhibits chaotic, heterogeneous, and often highly unpredictable geological structure. This makes it impossible to assess the quality of the rock mass using conventional categorization methodologies such as RMR (Rock Mass Rating) or GSI (Geological Strength Index). The challenges of tunneling in BIM rock were encountered in 3,6 km twin tube tunnel Golubinja, which is currently under construction in Bosnia and Herzegovina. Geological profile was initially assumed to consist of medium strong to weak, moderately to highly weathered shale, siltstone and sandstone of Jurassic age. During the construction phase, a significant discrepancy between the predicted geology and the actual conditions was encountered. The actual conditions were characterized by the presence of ophiolite mélange and ophiolithic crust sheets formations leading to a BIM type of material in which the matrix was formed of siliciclastic strata (graphitic phyllite) and blocks were formed of sedimentary and metamorphic rock. The designed short axis distance between the twin tunnels of 25 m led to a strong interaction between the tubes and presented an insurmountable obstacle for tunnel construction. Issues such as collapse of the primary lining and general instability were observed along the extensive sections of the tunnel. The reevaluation of the geological profile, increasing length of the axis distance between the tubes, and implementation of secondary lining as part of the support systems were carried out in order to enable buildability of the tunnel for given conditions. This paper presents key aspects of Golubinja tunnel construction including design approaches and remediation measures to overcome challenging BIM rock conditions.

This work focuses on obtaining and updating an inventory map of active landslides in the region of Sierra de Cartagena-La Union (Spain), a mountainous mining area in southeast Spain, by integrating space-borne InSAR and airborne LiDAR techniques. Ascending and descending Sentinel-1 InSAR datasets were processed to obtain LOS displacements. Moreover, open-access, and non-customized LiDAR point clouds were processed to analyze surface changes and movements. Then, active deformation areas (ADA) maps were semi-automatically derived from the InSAR and LiDAR results by using ADATool. The influence of rainfall was analyzed in detail by means of InSAR time series. The results not only highlight the effectiveness of these two remote sensing techniques (i.e. InSAR and LiDAR) to acquire inventory maps of active landslides in mining zones, but also emphasize the key role of rainfall as an important trigger for landslides.

The rains registered in Leon (Spain) during December 2019 created several problems on the railway platform: Line 130 Venta de Baños-Gijon, Section: La Robla - La Pola de Gordon. Damages were at the P.K. 26+700, where rockfalls happened coming from the rocky front located above the railway track. The rocks that come from the top reached the railway platform. A huge rock of approximately 50 t has exceeded the railway and has stopped on the edge of the town Puente de Alba. There are also some rocks, weighing slightly less than 10 t, which have remained next to the track. A statistical analysis of rockfall was done, to define locations of the mitigation measures and evaluated other practical solutions. Finally choosing the installation of the following systems: Rockfall drape system with TECCO® G65/3 high tensile-strength steel mesh, with horizontal reinforcement ropes and Rockfall barrier, 8 m high and energy absorption capacity of 8,000 kJ.

Wire meshes employed in secured drapery systems are constantly exposed to atmospheric corro-sion, resulting in diminished durability. The durability depends on the aggressiveness of the envi-ronment, unique to each location, and the protection of the wire, which is often poorly defined in projects. The applicable regulations include a classification of different environments (C2, C3, C4, C5, CX) based on their corrosivity levels. The class of environment serves as a technical character-istic to specify the necessary wire protection to ensure the stipulated service life. Steel wire prod-ucts typically have two types of protection: galvanic coatings, delivering electrochemical safeguard, and organic coatings, which create a physical barrier from oxygen. This article examines the perti-nent regulations, analyzing durability tests such as salt spray test and Kesternich test, different alloy alternatives, the projected service life for each environmental classification, and a case history re-garding this topic.

Many excavated weathered rocks have good initial stability but lose geomechanical properties until have behaviors similar to some soils, causing collapse of shoring. This is an analysis of different temporary shoring of excavations and their effectiveness reviewed with monitoring. The analysis reveals the relationship between excavation height and deformations. Likewise, it is observed that the incidence of the excavation stages and geometries has a greater impact on the deformations than the stiffness of the applied support.

Potash mining in Germany is thriving since more than hundred years, however reserves are limited, and many deposits will reach the end of its lifespan within the next decades. A new mining concept has been established to increase the lifespan of the mines and maximize the extraction rate of conventional mined potash deposits. The concept of secondary conventional mining utilizes the reduction of the dimensions of pillars to gain additional high quality crude salt. The supporting effect of the pillars is compensated by backfilling of the mined excavations, supported by a comprehensive long-term monitoring concept. The process of maximizing extraction rate with secondary conventional mining starts with mining of the pillar edges. The developed cavity is backfilled with rock salt (or residual material from the manufacturing). A backfilling grade of 90 % is aspired. In a next step the remaining pillar is excavated, leaving two small pillars at each end, which serve as short-term roof support until the remaining excavation is backfilled. With this procedure pillar after pillar are excavated until the whole mining area is backfilled. In preparation of this mining process rock mechanical investigation is done to proof a save mining process. It contains of a numerical modelling and an observation program. The numerical modelling bases on precise rock mechanical 2D and 3D models. The calculation evaluates possible hazards like pillar or field collapses and predicts the expected rock mechanical behavior. Then latter covers the mining induced effects to convergence and their impacts to barrier integrity as well as surface subsidence. The results show that the stresses in the barriers doesn’t endanger their integrity and the predicted surface subsidence is compatible with their normal use too. Bases on these results a monitoring concept is developed to observe the real rock behavior. It includes the development of convergence in the mining field, the released energy during and after the second mining process as well as the observation of surface subsidence – all bases on advanced observation methods. The comparison of the monitored results with the numerical prediction supplies a robust basis for a save mining process.

A massive rockfall event took place at the very entrance of a steep and large Đerdap Gorge on the Danube River in Eastern Serbia on 12-13^th of December 1974. Detailed engineering-geological examination of the site was undertaken at the time, but the event was never fully reconstructed. With the ascent of new surveying and monitoring technologies, and their greater availability in recent years it became possible to revisit such historical events and completely back-analyze them. Otherwise, the Gorge itself is rather active and constantly hosts minor rockfalls and other instabilities. An important international route passes along its base, where despite preventive and protective measures it remains highly exposed to rockfalls, whereas the river, i.e., the artificial lake itself, and the downstream hydropower plant and dam could be endangered by massive events, like in the 1974 when one third of the Danube River profile was dammed. The said event was triggered in an abandoned limestone quarry named Joc, arguably by several preconditioning factors: draw-down effect due to filling of the Đerdap lake that took place in 1972-1973, adversely oriented caverns subject to progressive failure, disturbed rock by heavy blasting in the past, lubrication along the adversely oriented joint set. In spring 2023, a field campaign targeted at ground surface mapping of the wider area was undertaken using advanced geodetic equipment, comprising of UAV Wintera and Mobile LiDAR scanner Leica Pegasus. The objective was to re-map the entire north face and surrounding topography and reconstruct the rockfall. The resulting point cloud depicts an irregularly jointed rock mass, likely disturbed by heavy blasting. The location of the source area was determined from the available field photos, and suggests that one large feature, placed amidst the slope, about 100 m above the road level was detached. It has been severely deformed and fragmented along the runout, so it has been transformed into a pile of rubble with large sized boulders. Total volume was estimated to 250,000 m³. The reconstruction was performed using a variety of tools, starting from simple 2D and 3D models that implement friction cone theory, to robust 3D models that consider complex geometry of collapsed material and detailed ground relief. Expectedly, robust models were more successful in reconstruction of the event, which was validated on the basis of known runout reach and debris height.

Urban sites in highlands or associated with rocky areas are common, giving them an admirable landscape richness and constituting a relevant part of their identity. However, this uniqueness is closely related to the risk posed by the degradation of rock formations, which generally results in the falling of blocks or, in the most severe cases, in landslides. Only in the past year, this phenomenon has occurred in locations such as Mijas, Almogía or Ardales in Spain. This article takes the example of Alcalá la Real (Jaén) to present a process and analysis model to quantify the geological risk factors in scenarios of rockfalls such as the one that took place in this town, which enables the assessment of the possible actions to be carried out with the aim of reducing these risks. It is important to remark the fact that, in most cases, one of the main premises is that the action should not have a major impact on the landscape. The underlying cause of the study carried out in the aforementioned municipality of Alcalá la Real was the fall of a large block on Calle Utrilla on a Sunday in summertime, as well as the risk of a further landslide affecting the pathways and houses located in the lower part of the hill. Once the block had detached, its fall by gravity put at risk the houses located at a distance of 125 ml. on a slope with a difference in height of 43 metres. The detached block had a volume of about 72 m³ and an estimated weight of 190 tons. The slope from which this block detached is formed by a level of bioclastic calcarenites supported by soft sandstones, sands and wall clays. The state of the outcrop before the instability occurred was conditioned by the strength of the material supporting the calcarenite levels and the fracturing system of the latter. The study considered several actions to be undertaken given the risk that more blocks could detach, quantifying and zoning the risks for each of the proposed actions.

The natural and cut slopes of a segment of the Dharasu-Uttarkashi Roadway (NH-108), located in the Lesser Himalayan Zone in India, have been studied adopting a multi-parametric integrated approach in terms of (1) distribution of magnitude of natural slope (2) engineering geological properties of intact rocks and rock masses, (3) kinematic analysis of slopes, (4) documentation of existing slope failures (5) rock- microstructural implications, (6) multiple geomechanical classifcation of slopes and (6) implications of active tectonics as deciphered from Neotectonic indices. Assessment of stability of slopes based on the combined study of the above parameters has been performed for twelve locations (L1−L12) on the road-cut sections where the slopes mostly have not yet failed. Magnitude of natural slopes overlooking the road section attains peak slope class of 41°−50°. Kinematic analysis characterizes the intact slopes in the above locations to possess conditions of wedge and toppling modes of failure, either in single or as combined. Existing failed slopes conform to combinations of planar, wedge, toppling and shallow circular failures. Rock microstructural study reveals development of strong shear-strength-weakening foliation anisotropy in the phyllites and schistose quartzites of the slopes that evidently serve as avenues of groundwater percolation and seepage and can promote failure along water soaked foliation planes that ‘day-light’ on the road-cut slopes at locations L1, L8 L9 and L10. Based on Geomechanical classifcation systems applied to slopes including Continuous Slope Mass Rating, Q-Slope and Hazard Index, new stability charts have been developed that classify the slopes at each location to be one of the three types: severely unstable, unstable or stable. Based on the new stability charts, road-cut slopes at all twelve locations were found to be unstable and slopes at three locations−L7, L8 and L10 were observed to be severely unstable, particularly hazardous and require immediate mitigation. From the erosional landscape of the study area, using several geomorphometric elements including ruggedness number (R_n), ratio of valley floor-width to valley-height, (V_f), stream length gradient index (S_L) and Hypsometric integral (H_i), an index of neotectonic activity (I_at) over the study area is obtained with an estimated value of 1.50 that indicates high neotectonic activity. Such high value of neotectonic index correlates with the high recent seismicity events documented from the zone containing the study area. Corresponding high neotectonic activity is expected to create steeper slopes due to deeper incisions and would potentially trigger failures in some of the currently stable slopes in the area.

Slope stability analysis is crucial for transportation projects in hilly areas, especially for road or tunnel portals. Various methods exist to assess slope instability, such as field-based, limit equilibrium, Numerical, and rock fall simulation. Among these, the field-based Slope Mass Rating (SMR) method is popular for initial assessments. In this study, a Windows-based Python application was developed to calculate SMR efficiently. The app quickly evaluates slope instability using provided data and allows users to input direct Rock Quality Designation (RQD) or estimate it based on joint spacing. It automatically calculates F1, F2, and F3 factors for all joints and identifies formed wedges due to joint interactions. The app generates detailed reports including joint attributes and ratings, aiding in slope stability interpretation. This user-friendly tool enhances slope stability analysis for project planning and generates technical reports for better project understanding.

Waste dump failures in coal mining pose significant safety risks, necessitating detailed post-failure studies alongside pre-failure deformation study. The post-failure studies evaluate the mobility of the failing mass, measured by parameters like runout length and width (i.e., runout characteristics). The understanding of the mobility of failing mass will help design a buffer zone around an overburden dump to restrict worker and machinery movement. This study, using a laboratory-scale debris flow flume, explores the effect of the composition of overburden dump on runout characteristics and the shape of debris flow fan. The findings of the experimental investigation suggest that while changes in relative proportion of fines and coarse particles (F/C ratio) affect both runout length and width, the effect on the aspect ratio may not show a straight forward pattern. The complex changes in aspect ratio imply that the overall shape of the debris flow fan may not be solely determined by the F/C ratio.

Elastic properties of rocks like Young’s modulus and compressional P-wave velocity are vital for understanding their stress-strain response in mining and rock engineering applications. Traditional methods for determining these properties involve labor-intensive, expensive and time-consuming. To address these challenges, this study proposes a novel predictive method. It utilizes a multi-layer perceptron feed forward neural network (MLP-FFNN) trained on grinding characteristics of ball mill to predict Young’s modulus and compressional P-wave velocity in sedimentary rocks. Laboratory experiments on limestone and dolomite samples generated extensive data, enabling development of prediction models using the proposed MLP-FFNN. The developed models demonstrate high predictive accuracy (R values: 0.952 for E, 0.987 for Vp) in training and good generalization (0.866 for E, 0.9707 for Vp) in testing, along with low Root Mean Squared Error (RMSE) values. These findings underscore the efficacy of neural network models in predicting E and Vp from grinding characteristics of ball mill.

Extraction of coal is done by both opencast and underground method of workings. The amount of overburden removal has increased significantly as the share of opencast coal mining has increased to ensure maximum recovery and greater depths. The accumulation of the removed overburden material as dumps at greater heights for the minimum ground cover area is an important task in the opencast mines due to which the dumps tend to fail. A dump failure can pause mining operations, endanger personnel and damage equipment. In some cases, due to lack of dumping space, the overburden dumps are laid above the underground excavations. The stability of the dumps over the old underground workings is a difficult task because of the stresses that are already developed due to the underground excavation. Therefore, it is paramount to study the stability of the slopes in this zone particularly when there was an old inaccessible extraction present within this zone. In this article, the prediction of stability of overburden dumps above the underground workings are studied by means of underground longwall working dimensions. A two-dimensional finite element analysis method is used in predicting the stability of overburden dump using RS2 software of Rocscience. Strength Reduction Technique is used for determining the factor of safety (FoS) of the overburden dump. From the modelling studies, it is summarized that the stability of the overburden dumps is being affected due to the presence of underground excavation with a vertical deformation of 0.0564m (56.4mm) for the critical strength reduction factor 1.12.

The Grassy Mountain mining project owned by Paramount Gold Nevada Corp. in the state of Oregon, USA has been developed for a Cut and Fill underground mining methodology with cemented backfill (CRF) operation. The present study analyzes the main variables involved in the manufacture and subsequent performance of cemented backfill, through a sampling process involving 12 CRF specimens prepared and tested by MetaRock Lab under the supervision of GMS, in order to obtain the UCS strength values of each one. Thus, 6 CRF specimens with 5% cement and 6 specimens with 7% cement were prepared, which in turn were subdivided into a curing time of 14 and 28 days. From the results of the UCS tests, the variables of cement percentage, sample density and days of curing are directly related to the strength of the CRF, obtaining better performances as these values increase. Finally, based on the benchmarking study, the performance of the CRF samples, according to the mix developed and proposed by GMS for the Grassy Mountain project, is within the expected range. The values for resistance, which is the main indicator to be highlighted, are in accordance with what would be expected according to the characteristics of the mixture, obtaining a maximum resistance of 6.14 MPa.

Due to rapid and extreme climate changes, in mountain and hilly regions infrastructures and people are more often treathened by rockfalls events. Falling boulders can have extremely high speeds, and these events involve a complex pattern of movement (e.g. detachment, fall, rolling, sliding, bouncing, etc) of one or more rock fragments. Rockfall Protection Embankments (RPE) reinforced with geosynthetics proved to be a safe measure for protecting people, structures and infrastructures from rockfall events, designed to absorb even very high impact energy (up to 30,000 kJ). RPEs can be constructed in various shapes and sizes, with different reinforcements (geogrids, geotextiles, geostrips, steel wire meshes, etc.) and facing materials (wrap-around, gabions, tires, etc.). The vast majority of existing RPE structures have been designed with basic approaches, considering dynamics only to a minor extent. The Authors have then developed a new analytical design method which consider the effect of all the variables playing a role in the resistance to penetration on the uphill face and the resistance to extrusion on the downhill face, in order to finally compute approximate yet consistent values of the penetration depth and of the extrusion length; hence the designer can quickly try different solutions and finally select the best combination of design variables which afford to respect all design limits and Factors of Safety. To the Authors’ knowledge, at present this is the only design method for RPEs which allows to take into account all the parameters contributing to the penetration and extrusion resistance, including the type and properties of geosynthetics, the layout and spacing of reinforcement in longitudinal and transversal direction of embankment, the type of facing, the properties of the fill and the geometry of the embankment. A back analysis of full scale tests is used to validate the presented design method.

Cheves Hydropower Project is in the Central Peruvian Andes, N of Lima that generates 825 GWh/year since 2015. The project includes approximately 20 km of tunnels and two caverns. The construction was done mainly in intrusive and the metamorphic rocks; generalized rock burst conditions took place, recording more than 850 stress-events. These events boost themselves in the presence of stiff rocks and geological structures, happening either at the face excavation or behind the face in the reinforced sections. The paper analyses all the factors related to the occurrence of stress-events: overburden, horizontal in situ stress, lithology and stiffness, joint sets and related structures and induced stresses; providing useful criteria, enabling designers to collect data and make some correlations that may be useful for other projects.

The Terradets Gorge is essential in the Catalan linear land infrastructure transport network. It serves as a natural boundary between Noguera and Pallars Jussà, facilitating a vital north-south connection for trade and tourism. In this area roads and railways traverse the gorge, despite facing elevations of rock slopes up to 500 meters. Recent incidents have highlighted their traffic vulnerability to rock falls and debris flows. Both administrations, Roads and Railways of the Catalan Government, have concurred addressing these chal-lenges between 2022 and 2023, enabling the comparison between infrastructure mainte-nance policies and revealing similar solutions for protection and mitigation. The experi-ence underscores the effectiveness of collaborative management in the face of geological risk in priority infrastructure corridors, where both authorities coincide. Sharing resources and strategies not only reinforces efficiency but also promotes cooperation among entities, enhancing resilience against future challenges

This paper presents a procedure of ill-posed problem back analysis of multiple landslides to de-termine the reliable shear strength parameters of rock mass. This procedure includes field in-vestigations, determination of instability mechanism, definition of collapse surface on the rep-resentative section, limit equilibrium stability analysis for variable shear strength properties, and limiting the range of possible answers. This procedure was applied for two individual complex translational-rotational landslides in Jajram Golbini No.07 mine. The investigations indicate the similarity and spatial correlation between the mechanical (shear strength) attributes of sliding surface of both landslides. This provide an opportunity to establish two equations for determination of shear strength parameters. Then, the cohesion and friction angle of rock mass were determined by solving these system of equations. The results of back analysis provide very useful information about shear strength parameters of rock mass and fault that can be ap-plied for reliable redesign of mine slope.

During the 19th century, coal mining in the underground of the Belmez urban area has caused subsidence with small cracks that are balanced by jumps of 1cm/year. Recently, a NW–SE direction cracking with distension of the mining roof terrain has been actived by the drainage of a mining operation and the emptying of two water deposits. A Namurian reverse fault that crosses Belmez on the surface has been reactivated as a dextral shear in the Kimmeric phase. By City Council request, this problem has been studied by comparing the natural tensions in the environment. Using a innovative Seismic Geotechnics, 30 m long NE-SW multi-channel reflection profiles are created for the seismic inversion of guided waves that allow to know the inelastic deformation of the terrain. Beneath this Namurian fault, there are the work-ings of coal layers from 40 m depth. The natural stresses, elastic moduli and friction angle have been obtained with the P and Svertical waves, which have been plotted, together with the inelastic Sradial geostatistics, up to 40 m depth.

In high-resolution research with Seismic Geotechnics, compression waves and three orthogo-nal shears are generated to obtain velocities based on the times of the reflected bands. Using an inverse process, the time domain is transformed into depth, up to 100 m, and distortion models are provided with underground images of natural stresses, friction angle, permeabilities, and elastic and inelastic modules using vertical and radial shear waves. By partitioning the energy of seismic waves at a discontinuity or interface, the initiation of rupture is proposed. Through the impact of energy on the heterogeneous ground surface, constructive waves in phase are reflected at the interface when impedance increases with depth and frequency remains constant. If imped-ance decreases with depth, the partition of the reflected wave presents a longer wavelength and is not constructive; it is out of phase, leading to tension and shear that generate pre-ruptures as deformation increases with the absorption of wave amplitude, resulting in the loss of contact be-tween particles. Results from the sliding model and classical mechanics can be compared; they are also applied in rock compression tests.

The Poggio Baldi Natural Laboratory, jointly managed by Sapienza University of Rome's Department of Earth Sciences and NHAZCA SRL, utilizes cutting-edge instruments like LiDAR, drones, radar, and more to monitor a critically stable rock scarp. It aims to understand connections between rockfalls and factors like geo-structural arrangements, thermal effects, seismic activity, and weather, with the goal of creating an early warning system. Research at the lab focuses on geo-structural characterization, analyzing block failure potential, and assessing rockfall hazards. High-res point cloud data and orthoimages help determine discontinuity orientation and rock block volumes. An innovative algorithm enables pixel-based stability analysis. The study compares data from different sources for analysis suitability and identifies active rockfall zones through 3D change detection. Simulations in these zones evaluate potential hazards. Overall, the lab's multidisciplinary approach using advanced tech enhances our grasp of rock slope dynamics in susceptible hilly regions.

The Scaled Span method is an empirical approach for calculating the stability of mine crown pillars: To determine the stability of the rock bridge between the void and the ground surface. It is a methodology that was born in Canada (Carter, 1988) at the end of the 1980s due to a series of problems and subsidence produced by sinkholes and collapses of shallow abandoned mines. The methodology has been refined over the years and has been applied in numerous countries, such as Canada itself, Austria, Spain, Peru, etc. The database has been increasing and the graph of this method makes it possible to establish both the degree of stability and the possible interventions to be carried out in the upper part of the mine or tunnel (since it has also been applied to shallow tunnels). The methodology uses the rock quality index Q and the dimensions of the void. Scaled Span means that the actual width of the cavity is “scaled” or weighted by other parameters such as rock thickness, length, etc. Volcanic caves or lava tubes are often shallow cavities on which buildings and infrastructures are sometimes built, and many of them are also visited by tourists. It is important for this to carry out an analysis of its stability. The most widely used approximation for the analysis of cave stability is the Q index (Jorda, 2016) but it has many limitations since it only considers geometrically the width of the cavity and not the cover thickness (with the exception of the SRF parameter). cave length, among others. For this reason, the scaled width is a good analysis methodology. In the present investigation, the use by its authors is compiled and extended to various volcanic caves in the Galapagos and Canary Islands, and it is concluded that it is a more realistic methodology than that of only Q-span and that it also provides reasonable protocols to follow for access or impediment to the cave.

In 2021, the Tajogaite volcano on La Palma (Canary Islands, Spain) emitted over 200 million cubic meters of volcanic materials, in the form of lava flows, lapilli and ash. Rebuilding damaged infrastructure, estimated in 1,676 buildings and 73.8 km of roads is a crucial priority. Additionally, it is important to explore potential uses for the products emitted by the volcano. Due to their basaltic nature, volcanic slag, lapilli and ash are suitable for manufacturing building materials such as cement, concrete, blocks or bituminous mixtures. This study focuses on the preparation of concrete tiles using products from the Tajogaite volcano. For this purpose, a laboratory-scale manufacturing procedure for concrete tiles was developed, with the premise of being as sustainable as possible, requiring low energy consumption and minimizing the emissions and waste generation. Various dosages of volcanic material were tested in order to check how it affects the samples performance, as well as to optimize the manufacturing process. The obtained materials were characterized using standard testing methods. Standard UNE-EN 1339 was used as a reference, which specifies the materials, properties, requirements and test methods for cement bound unreinforced concrete paving flagsr. The results of flexural strength tests indicate promising prospects for using the volcanic ash in the production of concrete tiles. However, further research is required to enhance products performance.

The Canary Islands is an archipelago of volcanic origin located in the northern Atlantic Ocean about 100 km from the coast of Africa. Numerous eruptive processes took place during its formation, emitting a large volume of volcanic material. The inhabitants of these islands have known how to take advantage of this resource, and historically, lithologies such as trachytes, basalts, trachybasalts, tuffs, ignimbrites or phonolites have been widely used as building stone. At present, the number of active dimension stone quarries is very small and most of them are concentrated in the islands of Tenerife and Gran Canaria. In the southern part of Tenerife, a pumice tuff known locally as "Canto Blanco" and a group of ignimbrites, with different tonalities, belonging to the lithological unit "Ignimbritas de Arico" are exploited. The extraction of these ignimbrites is carried out by the "Guama" quarry and are marketed under the name "Piedra Chasnera". Fracturing is one of the most important factors for assessing the suitability of a rock mass to provide commercially sized blocks for further processing. The main parameters to consider in a study of this nature are the direction of the joints and their distribution in sets, which define the fracturing pattern, and the spacing which controls the dimensions of the blocks in the rock mass. The main objective of this study is to evaluate the quality of the rock mass of the ignimbrite deposit of the "Guama" quarry. Firstly, given the importance of knowing the joint system to ensure profitable production, the main joint sets in the side wall of the quarry were identified. This evaluation is critical because the quarry owner plans expend the extraction as soon as the upper levels (paleosoil and topsoil) are removed. Secondly, the current exploitation front was analysed by characterising the discontinuities. By measuring the direction and length of the joints and using 3D Block Expert software, the spatial distribution of the fractures was assessed, which allowed to establish the size and volume of the effective blocks, i.e., defined by the natural fracturing.

The identification of rock mass discontinuities and their plane orientation is crucial for determining the characteristics of rock masses. Traditional methods of joint trace surveying can be challenging, time-consuming, and hazardous. However, non-contact measuring techniques offer the advantage of generating accurate objective records of rock masses and enable the measurement of discontinuities from digital surface models and 3D point clouds of outcrops without direct access to the rock mass and associated constraints. An innovative approach for identifying discontinuity planes in rock formations using 3D trace data has been presented in this paper. The concept of curved and straight traces has been introduced, with a curvature index indicating a trace's accuracy in representing its discontinuity plane. Additionally, co-planar traces have been identified by analyzing intersecting straight traces, further contributing to discontinuity plane determination. The methodology's effectiveness has been established through validation using a predefined 3D trace lattice resulting from discontinuity planes with known orientations on a 3D digital rock outcrop model. The methodology has then been applied to analyze 3D trace data from an actual rock outcrop, with successful results. The algorithm enables swift identification of main joint orientations, and this study represents an important advancement in the characterization of rock mass structural properties.

The area of Ollon, Switzerland is regularly subject to different ground instability phenom-enas like landslides due to the nature of its lithology. It is mostly composed of weathered gypsum and anhydrite. This study aims to investigate and characterize the causes of the landslide in Ollon in 2021 by analyzing topographic, historical, geological, and hydrologi-cal data. The last landslide occurred recently on the 1st December 2023.Our analysis ob-serves that the landslide was triggered by geological superficial soil alteration that goes along with a series of rainfalls. The investigation showed that the geological characteristics of the area, including the fast alteration process and steep slopes contributes to a high sus-ceptibility and frequency of landslides in this area.

Rock engineering activities, such as underground constructions, mining works, and excavation of rock slopes, are responsible of a wide range of changes in the surrounding environment. These effects can significantly alter the rock mass behavior over time, triggering different processes that negatively affect its stability. For this reason, monitoring activities aimed at improving the knowledge of the rock mass response are extremely relevant to ensure safety during construction and operation, check the validity of design hypotheses, and assess the necessity of risk mitigation measures. Overall, the design of effective monitoring systems requires a multidisciplinary approach that considers a range of factors, including geology, engineering, and data science, due to the inherent complexity of the subject. All these expertise play a key role in the development of a procedure able to provide critical information for safe and effective management of rock mass infrastructure. The first challenge involves the selection of the appropriate parameters to monitor. This requires a deep understanding of the observed element and the potential hazards that may arise, as well as the knowledge of the available technology for measuring and recording data. Due to the wide variety of physical quantities to sample, more advanced systems nowadays are designed to integrate multi-parameter devices, able to gather various information at the same time. The second challenge relates to the design of a system that can effectively collect and process the data. This requires careful consideration of factors such as the type and location of sensors, the frequency of data collection, and the method of data transmission and storage. The last key challenge in designing monitoring systems in rock masses involves the selection of the best approach for data integration, elaboration and management. This aspect is especially important when automatic instrumentation is implemented in the monitoring activity. These devices are, in fact, able to reach extremely high sampling frequencies, and the large volumes of data generated by such systems can be difficult to process and interpret. Additionally, it is important to ensure that the data is properly stored and easily available to facilitate its use in decision-making processes. This requirement can be fulfilled with the implementation of appropriate visualization platforms, designed to manage all collected information and to provide a reliable tool for their representation.