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Sandstone is widely distributed in cold regions and the freeze–thaw deterioration of them has caused many geological engineering disasters. As an important and direct index of frost resistance, the strength loss of sandstones under freeze–thaw actions should be investigated to provide a guidance for the stability assessment of geological engineering. In this research, the UCS (Uniaxial compressive strength) loss of six typical sandstones with different water contents after 0, 20, 40 and 60 freeze–thaw cycles was measured in the laboratory. The experimental results indicated that the freeze–thaw damage was more serious in sandstones containing high water contents, and the critical saturations for causing a significant loss of UCS under freeze–thaw were 60%-80% for these sandstones. Below this critical saturation, the UCS loss of the sandstones was mainly caused by water weakening rather than freeze–thaw damage. Besides, a developed strength prediction model was proposed by combining the exponential decay function and multiple linear regression method. The initial porosity, elastic modulus and tensile strength of fresh sandstones were a good parameter combination to accurately determine the decay constant in this developed model. The main novelty of this model is that it can accurately and easily estimate the UCS loss of sandstones after any freeze–thaw cycle only using the initial parameters of fresh sandstones, but it does not need to perform freeze–thaw and mechanical strength experiments. This study not only provides an accurate prediction model of UCS under freeze–thaw, but also makes a contribution to better understanding the frost resistance mechanism of sandstones.

Rock engineering is highly susceptible to cyclic loads resulting from earthquakes, quarrying or rockbursts. Acquiring the fatigue properties and failure mechanism of rocks is pivotal for long-term stability assessment of rock engineering structures. So far, significant progress has been gained on the mechanical characteristics of rocks subjected to cyclic loading. For providing a global insight of typical results and main features of rocks under cyclic loading conditions, this study comprehensively reviews the state-of-the-art of deformation and failure mechanism and fatigue constitutive relationship of rocks subjected to cyclic loading in the past 60 years. Firstly, cyclic tests on rocks are classified into different types based on loading paths, loading parameters, loading types and environment conditions. Secondly, representative results are summarized and highlighted in terms of the fatigue response of rocks, including the deformation degradation, energy dissipation, damage evolution and failure characteristics; both laboratory testing and numerical results are presented, and various measurement techniques such as X-ray micro-computed tomography (micro-CT) and digital image correlation (DIC) are considered. Thirdly, the influences of cyclic loads on the mechanical characteristics of rocks are discussed, including the cyclic stress, frequency, amplitude and waveform. Subsequently, constitutive relationships for rocks subjected to cyclic loading are outlined, in which typical fatigue constitutive models are compared and analyzed, regarding the elastoplastic model, the internal variable model, the energy-based damage model and the discrete element-based model. Finally, some ambiguous questions and prospective research are interpreted and discussed.

The present study is to assess the slope stability of road cuts along the National Highway 150 (202 present). Rock mass classification enables preliminary assessment of rock slope failure and guide the planners to choose suitable alignment for road construction and engineering structures. This technique includes collection of data from the intact rock and discontinuity parameters. Seven locations have been selected for slope stability analysis using RMR, SMR and CoSMR techniques. These empirical methods are used to determine the mode of failures and characterise the slope as well. Kinematic analysis deciphers the causes of instability and the mode of discontinuous rock failures. Results shows majority of road section between Ukhrul and Jessami falls under partial stable to unstable zone.

Soil restraints associated with relative soil-pipe movements is an important consideration for stability assessment of buried pipelines. This paper investigates the effects of pipe surface roughnes...

A particularly challenging aspect in gravity dam stability assessment is the estimation of the induced hydrodynamic water pressure when water with significant velocity is overtopping gravity dams and flowing in or over spillway components. The water flow conditions, including the related pressure fields and resultant forces, are difficult to quantify accurately. Herein, existing dam safety guidelines to estimate the weight of the overflowing water nappe on gravity dams with rectangular crests are first reviewed. Then, a computational fluid dynamics (CFD) methodology is developed to improve the simplified estimation of hydrodynamic pressure fields acting on the rectangular crests of submerged gravity dams. The CFD pressures are used as input data for the classical structural stability analyses based on the gravity method to more adequately quantify the dam stability during overtopping. A back analysis is also performed on the stability of an existing gated spillway that was overtopped during the 1996 Saguenay flood in Québec.

The adequate geological support and engineering of production processes requires mining companies to have structural geologists to be in charge for the acquisition, processing, analysis and preparation of geological and related data during development of a mineral deposit, starting from prospecting and exploration and up to reclaiming. In the prevailing practice, geologists of mining and servicing companies are mostly aimed at the appraisal and control of mineral resources while the study of geological structure of a deposit is assumed finished at the stage of prospecting and valuation as arule. At the later stages, geologists focus mainly on the quality and quantity of minerals, and geological bodies are often interpreted without regard to the actual geological structure of a deposit. The structural geology as a branch within a mining company should have a specific development strategy. This strategy is to account for the necessity of the other services for the input geological data, while the applied geological models should be used in mine design and be integrated in the production process. The intending specialists in the allied services should be informed on the available models, their value and completeness, as well as should possess free and intelligible access for operation. Efficient production management and risk control requires close communication between structural geologists, geomechanics, resource geologists, mining engineers, mineral dressing engineers and surveyors.

The freezing method is an effective approach for constructing coal mine shafts through water-rich soft rock strata. The frozen wall produced by this technique stops the movement of water and offers temporary support, ensuring the safety and stability of the shaft working face. However, most frozen rock masses generally comprise ice-filled flaws and frozen intact rock. A frozen fissured rock mass undergoing the long-term effects of excavation unloading under in situ stress gradually accumulates damage or creep deformation over time; this damage is mainly responsible for the significant deformation, cracking and even instability of the frozen rock wall. To study the creep characteristics of ice-filled fissured rock masses under unloading conditions, a series of conventional triaxial compression tests and triaxial unloading creep tests were performed on ice-filled flawed red sandstone specimens from the Shilawusu mine in Northwest China using a self-developed DRTS-500 subzero rock triaxial testing system. In conjunction with the experimental data, the instantaneous strength and deformation characteristics of the rock specimens were analyzed, and their creep deformation characteristics and damage evolution characteristics were discussed. In this paper, based on the nonlinear creep characteristics of frozen rock, fractional calculus theory and damage theory, a new nonlinear creep damage model of frozen fissured red sandstone was defined in series with the improved Burgers model and elastoplastic damage model. The proposed creep model can reasonably describe the creep deformation of frozen fissured red sandstone. Classical elastoplastic mechanics and creep theory were used to derive the three-dimensional creep damage constitutive equation, and the results of creep experiments and simulation results of the creep damage constitutive model were very consistent in this study. The new creep model not only reflects the whole creep deformation process of frozen fissured red sandstone but also exhibits better performance than the classical Burger model and improved Nishihara model in describing the primary creep stage and accelerating creep stage. Therefore, the proposed nonlinear creep damage model is suitable for studying the mechanical creep properties of frozen fissured rock under unloading conditions. The results can provide an important reference for the long-term stability assessment of frozen rock walls of coal mine shafts.

This work focuses on integrated stability assessment of rocky tunnel slopes along a planned railway, namely, the Dujiangyan City to Siguniang Mountain Railway (DS Railway), which is an important transportation corridor in Southwest China. Investigating the stability of slopes at the entrances and exits of tunnels represents the first step of railway construction. Based on detailed geological engineering studies, the stability of 32 tunnel slopes was measured and evaluated by means of the slope mass rating (SMR), Chinese slope mass rating (CSMR) and Chinese continuous slope mass rating (CCSMR) systems. Moreover, a kinematic analysis technique was also employed to identify the potential failure modes of the jointed rock masses in tunnel slopes. The results reveal that the CSMR, by considering the slope height and discontinuity condition coefficient, can more robustly assess the slope stability than the SMR. Similarly, the CCSMR, which is based on continuous functions and can identify potentially dangerous slopes that should be reinforced, can reduce subjectivity. Many slopes deemed unstable and completely unstable by the CSMR and CCSMR are located on the banks of the river from Longchi to Longtan and from Xindianzi to Siguniang Mountain. The potential failure modes of the 32 slopes determined by kinematic analysis are basically consistent with the results obtained by the slope mass classification systems. These research results pave the way for stability assessment and intervention decision-making during the construction of the DS Railway.

Landslide dams are formed mostly in V-shaped valleys, with poor stability and a high risk of failure. Once landslide dams fail, they may cause floods or debris flows that endanger lives, property, and infrastructure downstream. Therefore, it is important to evaluate the stability immediately once a landslide dam is formed. The geometry of a landslide dam is the most critical to its stability assessment. However, the complex terrain and geomorphological conditions in the disaster area often make field surveys difficult. Aerial photography and satellite imagery technology are usually limited by poor weather conditions, which bring severe restrictions to the timely acquisition of the geometry of a landslide dam. In this paper, a discrete element simulation model was proposed and verified by two experiments, and then a series of numerical simulations were performed to investigate the geometry and formation process of landslide dams under different topographic factors including the motion path dip-angle, the river bed inclination, and the angle between valley slopes (valley angle). The results show that the geometry and formation process of landslide dams are significantly affected by the topographic factors. According to the results of comprehensive numerical analysis, a simple predictive model for landslide dam geometry in V-shaped valleys was established, and two landslide dams with data collected from early events were employed to validate the predictive model. Based on the easily accessible topographical factors, the proposed model accomplished the fast prediction of landslide dam geometry. This research provides a vital basis for the stability evaluation of landslide dams and can be used for the disaster emergency response before the dams break.

The Malogne Phosphatic chalk quarry was developed by the rooms and pillars mining method within an area of 67 ha. The site is partially flooded and located in close proximity to important infrastru...

Background: Cellular cofferdams are a temporary construction consisting of interlocking steel sheet pilings driven into the ground as a series of interconnecting cells. Objectives: This study aims to investigate the stability of cofferdams with a circular diaphragm due to lateral load in dry and wet soil cases. Discussion: A series of laboratory tests were performed on different width to height ratios (0.8, 0.9, and 1.0), berm ratios (0.2H, 0.3H, and 0.4H), and embedment depth ratios (0.2H, 0.3H, and 0.4H) with four types of soil fill (clay soil, river sand, sand passing sieve No.4, and sub base). The coupled circular cofferdam-soil system was modelled using nonlinear finite element analysis (COMSOL Multiphysics Software) to validate the experimental results. Conclusion: After applying hydrostatic, hydrodynamic, and structural failure loads, the resistance of the cellular retaining structures with wet soil fill in saturated soils was greater than with dry soil fill in dry soils. The most advantageous construction format was found by deciphering the relationship between the aforementioned loads and berm ratios, embedment depth, and horizontal displacement.

Roads are generally affected by slope failures, and these failures can increase when there are weathered materials and high rainfall. These circumstances occur in the sub-Andean zone of Ecuador. This is the region where the study area is located. The stability of a stratified rock slope, which is affecting a section of highway E45, was evaluated. The study slope is exposed to the road, but the upper part is covered by a soil-type material and dense vegetation that makes it challenging to study. We applied the Q-slope method and seismic tomography; these methods used together worked well, because they allowed to correlate and infer information about the quality of the rock mass, even in a fast and economical way. We also performed core drilling with core recovery in the crown of the slope and SPT test. The slope presented two well-differentiated zones; therefore, Q-slope values were calculated for each of these zones. The results show that the slope is unstable. The application of seismic tomography as an input parameter for calculating Q-slope was important because it allowed evaluating the stability where it is impossible to collect geomechanical information, correlate information taken at the foot of the slope, and define the depth of the bedrock.

Large-scale slope destabilization could be aggravated due to swift urbanization and ever-rising demands of geoengineering projects such as dams, tunnels, bridges and widening roads. National Highway-58 connects Delhi to Badrinath in India, which passes through complex geomorphological and geological terrain and often encounters cut slopes susceptible to slope failures. In the present investigation, a detailed geotechnical appraisal is conducted along the road cut slopes from Rishikesh to Devprayag in the Himalayas. Twenty vulnerable road cut slopes were demarcated for detailed slope stability analysis using Phase2D finite element modeling simulator. Nonlinear generalized Hoek-Brown (GHB) criterion was adopted for stability analyses. Out of 20 slopes, five slopes (S6, S7, S18, S19 and S20) are unstable with factor of safety (FoS) less than or equal to 1, and thus needs immediate attention. The FoS values of four slopes (S2, S9, S13 and S17) lie between 1 and 1.3, i.e. marginally stable, and slopes S1, S3, S4, S5, S8, S10, S11, S12, S14, S15 and S16 are stable. Mohr-Coulomb (MC) criterion was also adopted to compare the slope stability analysis with GHB criterion. The FoS calculated from GHB criterion is close to that using MC criterion for lower values of FoS whereas for higher values, the difference is marked. For the jointed rock in the Himalayan region, the nonlinear GHB criterion gives better results as compared to MC criterion and matches with the prevailing field conditions. Accordingly, some suggestions are proposed to strengthen the stability of cut slopes. Keywords: Landslides, Numerical modeling, Finite element method (FEM), Slope stability

Stress relaxation plays an important role in the design of underground stopes. The aim of this paper is to assess the stope stability in connection with the stress relaxation using a classification...

Stability assessment of slopes has historically been performed assuming soils to be homogeneous in two-dimensional (2D) cases. In real cases, soils are usually inhomogeneous, and each slope collapse indicates a three-dimensional (3D) nature. Based on a 3D rotational failure mechanism, this work develops an approach to account for the impact of the vertical strength inhomogeneity on the 3D stability of stepped slopes. Seismic actions are taken into account by introducing the concept of a horizontal seismic coefficient. An upper-bound expression for stability factors is derived in the light of the kinematic approach, and the most critical solution is obtained from an optimization programming. In comparison with the previously published solutions, the validity of the proposed method is shown. A sensitivity analysis is carried out to discuss parametric effects on the stability of 3D stepped inhomogeneous slopes.

Rock support systems have become widely dominant components in underground hard rock mines. They are used to maintain the stability of underground openings and reinforce disturbed rock masses after creating an excavation or starting mining activity. Thus, the objective of this study is to examine the effect of support types on the performance stability of underground tunnels that exist in hard rock mines, in terms of deformation, the extent of failure zones and the strength of the rock mass surrounding the tunnel. This, in turn, will help in the selection of an appropriate support system that mitigates the stress-deformation conditions around the tunnel. Herein, four models have been built using the RS2D program, simulated and introduced to evaluate the behaviour of an underground tunnel with different rock support systems. The first model is simulated without any support system, whereas, rock bolts have been installed in the second model. The third model applied only shotcrete, while rock bolts and shotcrete are combined together in the fourth model. The results are presented and discussed in terms of strength factor, the extent of yielding zones and rock mass displacement/convergence. The results show that tunnel stability suffers when there is no rock support at all, while, it is significantly improved when the rock support system is installed. The optimum improvement is obtained when both shotcrete and rock bolts are employed together., Potporni stijenski sustavi široko se koriste u podzemnim rudnicima čvrstih sirovina. Njima se održava stabilnost podzemnih prostorija i ojačavaju se oslabljene stijenske mase tijekom iskopavanja ili miniranja. Cilj istraživanja bio je ispitati utjecaj vrste potpora na stabilnost podzemnih tunela u rudnicima čvrstih sirovina, na širenje zona oslabljenja i stabilnost stijena koje okružuju tunele. Na taj način moguće je odabrati odgovarajući potporni sustav koji ublažava deformacije prouzročene stresom. Načinjena su četiri modela uporabom programa RS2D, kojima se simulira i procjenjuje ponašanje podzemnih tunela s različitim potpornim sustavima. Prvi model simulirao je slučaj bez ikakve potpore, drugi slučaj uključio je stijensko sidro, a treći isključivo mlazni beton, dok je četvrti temeljen zajednički na stijenskome sidru i mlaznome betonu. Dobiveni rezultati raspravljeni su s obzirom na faktor naprezanja, prostiranje zona smicanja te rasjedanja. Opaženo je kako je stabilnost tunela, očekivano, najmanja u slučajevima gdje potpore nema, dok je znatno veća kada takav sustav postoji. Optimum je postignut kada su zajednički primijenjeni mlazni beton i stijensko sidro.

Landslides are complex phenomena, and the main factors that have a significant impact on their behavior are changes in slope inclination geometry and changes in water conditions. The main purpose of this work was to evaluate current conditions of the landslide in Brzozowka, near Cracow (Poland), and analyzing how different saturations of soil influence the stability of the landslide. The combination of geophysical and geotechnical research, such as electrical resistivity tomography (ERT), cone penetration testing, drilling and laboratory tests as well as a comprehensive analysis of their results, provided reliable information on the geological structure and geotechnical parameters of the landslide. The results were used in numerical simulations of the landslide stability, in which a two-phase model (soil and water) was assumed that included the effective soil strength parameters and the transient flow conditions as well as a partial saturation zone. The sliding surface obtained from the numerical modeling was almost flat, which was confirmed by the ERT method. It was proved that the landslide occurred when the saturation of the upper part of the slope exceeded 0.8. Obtained results are useful for engineering practice.

A structural and engineering geological study of rock slope stability was carried out in six stations that lie in the Southwest of Baranan mountain, along Sirwan road. The rock slopes and discontinuities were surveyed at each of these stations, and the relationships with failures were determined. The slopes were classified on the basis of (Al-Saadi, 1981), and the rocks were described in engineering terms according to (Anon, 1972) and (Hawkins, 1986), Stereographic projection was made using software (GEOrient 9.5.0) to represent the field data that were recorded in order to understand the situation in the six stations (sites) that were chosen along Sirwan road near Darbandikhan dam, the failures' types were recorded during field study were rock fall, toppling, and sliding. The study also revealed that the factors affecting slope stability in the study area were slope angle, height, dip of strata, and discontinuities. The laboratory test of the rock samples (point-load test) showed that the average value of compressive strength of the rock for the study area is about 181.29 MPa.Some measures are proposed to stabilize the slopes in the mentioned stations including; the removal of blocks liable to toppling in the critical cases (sites 2 and 6), casing the slopes with covenant materials such as concrete (site 4) and gabions (sites 2 and 6), with construction of retaining walls and digging of protective trenches to protect the slopes and reduce their hazard on the road (site 1, 3, and 5).

This paper presents the stability assessment of a century old coalmine situated under a railway track. The mine openings may lead to the surface subsidence which can endanger the track safety. To assess the stability, this paper presents a unified approach of observational, empirical, and analytical methods. Observational approach monitored the immediate roofs with geotechnical instruments during a period. In empirical approach, the coal pillar safety factors were assessed using rock mass classification. Finally, the analytical study was performed using numerical simulation. All these studies found that the openings and the coal pillars are stable for the track safety.

The stability of three-dimensional (3D) slopes with cracks is presented based on the kinematic approach of limit analysis. The sequence quadratic program optimization procedure is applied to obtain the least upper bound results. The most critical crack, including the crack depth and crack location in the 3D slope, is discussed. To provide a quick reference of the slope safety factor, stability charts are presented. The geometry of the critical failure surfaces, including the most unfavorable cracks for slopes with different width constraints and inclinations, are analyzed as well. Conclusions can be drawn that the critical height of the slope reduces due to the presence of cracks. A larger reduction in the critical height of slopes is found under plane strain conditions, compared to that under three-dimensional conditions. This reduction drops, however, with decreasing slope inclination angle. In addition, when compared with plane-strain conditions (slope width approaches infinity), the 3D slopes (with limited width) exhibit shallow sliding characteristics.

There are many places in the different countries of the world where working in the underground mines have been done below surface structures such as railway lines, roads, buildings, villages/residential colonies, pipelines, etc. The workings are generally old, abandoned and presently unapproachable. In some places, important delicate surface structures are installed above a portion of old abandoned underground workings. Safety of these important surface structures above old underground mine workings is a serious concern in many countries all over the world. Many times, it is difficult to move or divert these surface structures due to a number of reasons including technical problems, the involvement of huge expenditures and socio-economic issues. There is a need to assess the stability of these places and the procedure to stabilise the places if found unstable to make the structures safe. Hence, there is a need of proper stability assessment of the ground below these surface structures. The railway line is one of such important structures, where stability should be ensured for the safety of the passengers. In India, many underground workings are present below railway lines. Most of the workings are old and unapproachable and their stability status is in doubt. Dismantling or diverting of the important railway lines is a high-level policy matter and involves huge time and money besides complicated socio-political issues like the rehabilitation of the affected people. But the safety of the commuters using railways passing over the coal-bearing areas having mining activities cannot be compromised. Therefore, it is highly preferable to take protective measures instead of dismantling and diversion of lines, wherever possible. It is necessary to establish the position and dimension of the inaccessible underground workings below these types of important surface structures and carry out its stability analysis to take appropriate protective measures for the safety of the structures and commuters. This paper highlights the delineation procedure of the unapproachable underground roadways below surface structures with special reference to railway lines and its stability evaluation with case studies. Appropriate protective measures have also been suggested which are proved to be effective and validated the results of the study.

This research was conducted in an area around AlemKetema, North Showa, central Ethiopia; with a general objective of conducting a rock slope stability assessment on the selected natural rock slope sections. To achieve this objective, slope stability probability classification was followed to determine the stability probability conditions of slope rock mass in the study area. These classification systems mainly depend on the primary data collected from field works. As a reason, systematic and extensive fieldwork was conducted. However, secondary data was also required to characterize the general conditions of the study area and to have a deep understanding of the subject matter. In the SSPC system, ratings for the degree of weathering, intact rock strength, method of excavation, roughness condition, and infill material were given according to standards. The slope stability probability classification (SSPC) system practices three-step classification systems. These steps are exposure rock mass, reference rock mass, and slope rock mass. Following these steps, slope rock mass stability probability classifications have been carried out for 92 natural rock slope sections. The stability of slope rock mass was determined by two different approaches namely orientation-dependent and orientation independent stability. Orientation dependent stability is linked with the orientation of the discontinuities and characterized by toppling and sliding criteria, while orientation independent stability is linked with the strength of slope rock mass. Accordingly, the overall assessment indicated that 80.4% of rock slope sections showed less than 5% stability probability, 10.9% of rock slope sections showed from 5 to 49%, 6.5% showed from 50 to 95%, and the rest 2.2% of rock slope sections showed greater than 95% stability probability. All these results were compared with the visual stability assessment results. Accordingly, different stability probability maps were produced.

Fishbone-shaped dikes are always built on the soft soil submerged in the water, and the soft foundation settlement plays a key role in the stability of these dikes. In this paper, a novel and simple approach was proposed to predict the soft foundation settlement of fishbone dikes by using the extreme learning machine. The extreme learning machine is a single-hidden-layer feedforward network with high regression and classification prediction accuracy. The data-driven settlement prediction models were built based on a small training sample size with a fast learning speed. The simulation results showed that the proposed methods had good prediction performances by facilitating comparisons of the measured data and the predicted data. Furthermore, the final settlement of the dike was predicted by using the models, and the stability of the soft foundation of the fishbone-shaped dikes was assessed based on the simulation results of the proposed model. The findings in this paper suggested that the extreme learning machine method could be an effective tool for the soft foundation settlement prediction and assessment of the fishbone-shaped dikes.

Mechanised depillaring (MD) has been proved to be a panacea for faster extraction of the developed pillars which is blocking access to deeper deposits and locking more than 3200 Mt of coal, developed by Bord and Pillar mining method in Indian coalfields. Depillaring of these square/rectangular-shaped developed pillars by continuous miner creates irregular-shaped ribs/snooks. Stability assessment of such ribs/snooks becomes a challenging task due to various issues faced in estimation of load acting upon it and their strength. Area-based approach for the design of rib/snook is found to be the most suitable criteria during MD. Field investigations supported for parametric investigation for a competent size of rib/snook with varying nature of roof and depth of cover. Taking help from previous studies to design such ribs/snooks on numerical models using FLAC3D, a parametric study is carried out using 3DEC. Strength of such ribs/snooks and load acting upon them is calculated with the help of calibrated numerical models in order to estimate their factor of safety. This paper presents a review of the previous researches and a novel numerical simulation technique for estimation of a competent size of rib/snook in a given geo-mining condition.

Evaluating the shear strength of mine waste rock containing particles of metric scale is challenging because commercial laboratory testing devices can only accommodate samples composed of particles a few centimetres in size. The shear strength empirical model of Barton & Kjaernsli (1981) is therefore frequently used to assess the non-linear shear strength of very coarse granular material for stability assessment of very high mine waste dumps. In this article, we discuss practical methods for collecting the information required as input to the model, and we also illustrate the implementation of deterministic and probabilistic approaches for estimating the shear strength of several waste materials from a banded iron formation located in the Pilbara region of Western Australia.

The stability of high rock slopes has become a key engineering geological problem in the construction of important projects in mountainous areas. The original slope stability probability classification (SSPC) system, presented by Hack, has made obvious progress and been widely used in rock slope stability analysis. However, the selection and determination of some evaluation indexes in the original SSPC method are usually subjective, such as intact rock strength and weathering degree. In this study, the SSPC method based on geological data obtained in the prospecting tunnels was presented and applied. According to the field survey and exploration of the prospecting tunnels, the weathering degree of the slope rock mass was evaluated. The empirical equation for the maximum stable height of the slope was applied to the slope stability evaluation in the presented SSPC method. Then, the slope stability probability of numerous cutting slopes in the sandstone unit was evaluated using the presented system. Results of the Geostudio software based on the limited equilibrium analysis of the investigated slopes were compared with the results obtained by the SSPC method. The results indicate that the SSPC method is a useful tool for the stability prediction of high and steep rock slopes.

Collapses of expressway embankments due to large earthquakes and heavy rainfalls have been reported. Those collapses often closed important transportation routes and resulted in serious damages in communities. Inappropriate groundwater treatment and slaking/weathering of embankment materials contribute to these collapses. In order to diagnose road embankment soundness, we have to visualize the inside the embankment. The automatic technology for surveys and evaluations of embankments by using surface wave logging and electric resistivity logging has been proposed. We performed initial diagnostics before the opening of the expressways to evaluate embankment materials and stability of the embankment, especially in the vicinity of the stiff structures, such as box culverts and around the boundary between embankment and cut section. The desired target inspection speed, 500 m per h (mean speed), was achieved. The stiffness of embankment was continuously obtained for many sections with different fill materials as the initial reference data for future inspection. Based on the comparison between initial reference data and those obtained in the future, it is possible to select the optimal countermeasures to ensure the continuous stability of the road embankment.

Dangerous rock mass in the overhanging slope of Puerdu town has good free-face condition, high position, and great potential energy, identification and stability evaluation of which is a difficult problem in the disaster prevention. In this paper, the limit equilibrium method was used to evaluate the dangerous rock mass stability in the overhanging slope. Firstly, geomorphic characteristics and the distribution of dangerous rock mass are determined by the field geological survey. Secondly, six dangerous rock masses which may cause more threat are studied, with defining their failure modes and characteristic parameters. Finally, a simplified geological model is established, the stability coefficient of dangerous rock mass under different conditions is calculated by the limit equilibrium method, at the same time, stability analysis of dangerous rock mass is carried out based on the stereographic projection, and the hazard probability is estimated by the empirical formula. Results show that joints obviously developed in the dangerous rock mass of W1, W2, W3, W4, W5, and W6, with falling-type and toppling-type failure modes. In the natural condition, the dangerous rock mass is understable and unstable under the rainstorm and earthquake conditions. Consequently, rainstorm and earthquake are the key triggering factors of the instability and collapse of dangerous rock mass.

In the present study, slope stability assessment of selected cut slopes on a road stretch of approximately 25 km length along the National Highway (NH-58) between Shivpuri and Kaudiyala in the Lesser Himalaya of Uttarakhand has been carried out. This NH-58 connects Rishikesh with Badrinath and Kedarnath, two important Hindu shrines in Uttarakhand and also the border areas of the country. Hence, it is obvious that this highway is important from the pilgrimage, tourism and defense point of view. The present study includes characterization of rock mass, computation of slope mass classification ratings and comparison of different rock mass classification systems (such as RMR, GSI, SMR and CSMR) for 25 numbers of rock slopes along the selected road stretch. Also, kinematic analyses have been performed for all these slopes to understand the mode of slope failure. Further, stability analyses of a few significant road cut slopes have been carried out using a finite element tool.

Pressure arch utilises the self-stabilizing capacity of surrounding rock and is benefit to the roof stability of underground excavations. The analysis of it provides a new stability assessment tool...

For preservation efforts and stability assessment of historic structures it is imperative to understand the extent of existing damages and possible modes for how they could have occurred. The aim of this work is to illustrate the importance of integrating documentation, non-destructive testing, and numerical modeling for damage assessment of heritage structures. In particular, this work explores the synthesis of these techniques on a plastered masonry wall in Palazzo Vecchio. Laser scanning was used to capture the geometry of the wall while terrestrial photogrammetry and high-resolution images were used to document the magnitude of cracking in the plaster layer. High resolution thermal images were used to document the distribution of stones and additional cracks not visible through the plaster layer. The results of documentation and non-destructive testing were used to generate an as-built model for structural analysis. Finite distinct element modeling was used to simulate the response of the wall to a series of loading conditions. By comparing the results of simulation to existing crack patterns, theories for how the damage occurred were generated.

To ensure the stability of a deep underground complex during its construction and operation, it is important to understand its deformation and failure behaviors before its construction. In this study, taking China’s first underground research laboratory (URL) for the geological disposal of high-level radioactive waste (HLW) in Beishan area as engineering background, we carried out large-scale three-dimensional (3D) geo-mechanical model tests on a deep underground complex consisting of a shaft and three intersecting tunnels. Based on the self-developed 3D loading system, the miniature excavating apparatus and the analogous material, the stability of the underground complex during its excavation and under overloading are systematically evaluated. The test results effectively reveal the deformation and failure behaviors of the underground complex. The interactions between adjacent excavations are elucidated. The overloading safety factors are obtained from the overloading test: the safety factor of crack initiation is between 1.5 and 2.0; the safety factor of local failure is between 2.0 and 2.5; and the safety factor of overall failure is between 2.5 and 3.0. The test results provide important guidance for the stability evaluation of the URL in construction and operation. These results also provide an ideal data set for the calibration and validation of numerical models to simulate the deformation and failure of underground structures.

This paper addresses a stability evaluation of artificial slopes in a quarry located in Slovenia that was affected by a rockslide in March 2019. In order to ensure the safety of further production, measures were taken to restore the slopes. A stability assessment of the remaining parts of the quarry was conducted. To ensure quality spatial data, an upgraded study based on terrain mapping and aerial photogrammetric imaging using an unmanned aircraft was carried out, in addition to a traditional field survey of the quarry. So that the data were qualitatively useful, a digital terrain and discontinuity model was developed. Projections of the discontinuities occurring in the quarry and in the wider area were determined. The focus of the modeling was finding the main systems of discontinuities and projecting these systems onto the unexcavated parts of the quarry.

Sudden inelastic deformations in rock are associated with acoustic emission (AE). Therefore, AE monitoring technique can be used to study the fracture processes of rock. In this paper, AE tests were conducted on the granitic gneiss specimens under the uniaxial compressive loading conditions. The temporal changes in AE hit parameters and spatial-temporal evolution of AE events during the failure process of the granitic gneiss specimens were studied, and several characteristic AE phenomena (i.e., dramatic increase in dominant frequency, AE energy, and hit rate, the AE event with a high energy level, and the through-going distribution of the AE events with intermediate energy levels) were statistically analyzed before the failure occurred. It was found that the chronological order of the characteristic AE phenomena was relatively certain and correspondingly had a close relationship with the crack development stage. Because of the difference of the stress level at each crack development stage, the stability at different crack development stages is different. Therefore, a rock stability assessment approach was established based on the chronological order of the characteristic AE phenomena, and then the rock stability was assessed using the proposed approach.

Laser scanning has proven useful in the stability assessment of underground openings. High accuracy points are used to generate 3D surface models to evaluate their stability by assessing rockmass structural features. A series of scans obtained from underground ancient quarries in Paros Island were processed. The structural analysis of the openings was complemented by field observations and measurements, serving as input parameters for numerical software used to evaluate the potential failure mechanisms and overall stability. Blocks with a higher risk of detaching are encountered mostly at tunnel portals where support is required to secure unstable blocks to preserve this geotope.

This paper presents the details of the geotechnical investigations carried out to evaluate the performance of the misaligned Mechanically Stabilized Earth (MSE) wall in India. The reported MSE wall is part of the approach to the railway over bridge in Hyderabad-Bangalore highway. The MSE wall of height 13.85 m was misaligned vertically after the highway was opened to traffic in 2010. Initially, the only option seemed was to dismantle and reconstruct the MSE wall. However, the detailed geotechnical investigation revealed that the existing wall can be retained with minor repair works. As part of the geotechnical investigations, both field tests and the design analyses were performed. The field tests included standard penetration test, multichannel analyses of surface waves, and ground penetrating radar. The design analysis included the stability assessment of the MSE wall using SLIDE software. The results of the investigations revealed that there was no structural instability in the wall. The major cause of the misalignment was attributed to poor construction practices. As part of the rehabilitation, minor repair works were performed. After the completion of the rehabilitation, the wall has sustained heavy traffic loads in the past 5 years without developing any additional misalignment or cracks.

The problems of stability assessment of the quarry’s southern side during the development of the coal seam D6 are considered. To assess the stability of the quarry’s southern side in the development of coalbed outlets, modern research methods are applied: study of the geological structure and analysis of the adjacent rock mass state, the creation of an observation station and the production of observations, calculation of stability of adjacent rock mass of the quarry’s south side and the research results analysis. Quarry’s south side consists of clayey sediments up to 5 m, then siltstones and mudstones up to 10-20 m and a coal seam with a capacity of up to 5 m. The substantiation of the calculated strength characteristics of rocks composing the slopes of the quarry ledges, which determine the stress state of the slopes arising under the influence of internal and external forces, is done. Instrumental observations of the laid station and the survey of cracks on the quarry’s side allowed to determine the contours of the deformation zone and the landslide prism size. A geomechanical model of adjacent rock mass was created and the stability assessment was carried out for the geological section along the line of the maximum development depth. After additional loading on the quarry’s southern side slopes, the safety factor of stability is nу = 1.69−173, which means active phase termination of quarry’s side deformation and sustainable condition.

Over the last decades, constructions of large underground rock caverns are experiencing a rapid development across the globe. However design and construction of these structures is a complex and challenging task, specifically with limitations of limited investigations data and presence of many uncertainties. Rock mass parameters along with joint configuration such as persistence, spacing and strength of the joints are the main factors which significantly modify stresses and displacements in the vicinity of the openings. Thus, a detailed cavern stability assessment based on field data collection from the excavated cavern’s face is critically important. This paper discusses continuum and discontinuum modelling of underground rock caverns based on case study of crude oil storage project located on southern coast of India. Critical points of observation for these two types of analysis are reviewed in reference to results of the case study. Data obtained from geotechnical monitoring of underground rock cavern is also compared and discussed with the results obtained from both continuum and discontinuum analysis for better understanding of the same. The results obtained from this study indicate that inclusion of discontinuities in rock mass for numerical modelling captures essential instability conditions around the cavern while continuum representation gives a more idealised illustration of the instability. Observed displacement values in most of the cases lie in between the calculated displacement values of continuum and discontinuum analysis.

An assessment of stability potential of rock slopes from Ranau, Sabah has been conducted using modified D-slope method. D-slope comprises of G-Rating determination and Potential Instability to assess the slope condition using field observations, laboratory analysis and microfabric analysis. 17 parameters have been done for G-Rating purpose including the type of rocks, weathering grade, existence of faults and joints, number of major sets, number of orientations, aperture, persistence and spacing of discontinuities, rainfall, hydraulic condition, height of slope, history of instability, porosity, strength, micro-petrographic and micro-fractures index. Kinematic analysis is used for Potential Instability analysis to determine the type of failures for each slope. This later is to determine the level of slope’s risk: No Risk, Low Risk, Moderate Risk or High Risk. Six slopes have been chosen from Trusmadi Formation and ultrabasic Rocks along Marakau – Ranau Sport Complex. Based on the results of G-Rating, only slope S1 and S4 have value more than 0.4 while other slopes have less than 0.4 which indicates stable slopes. Based on kinematic analysis, all slopes experienced wedge failures with S4 and S5 also have planar failure possibility which show that all slopes have potential instability. D-slope analysis indicates that slope S4 is considered as Moderate Risk with mitigation suggestions are rock anchor and soil nailing with further actions required. Slope S1 is categorized as Low Risk with suggestions of stream system inspection and vegetation on exposed area of the slopes, while other slopes (S2, S3, S5 and S6) have no suggestion for mitigation as been assessed as No Risk.

The stability of the limestone cliff at Gunung Kandu, Gopeng, Perak, Malaysia was assessed based on the Slope Mass Rating (SMR) system on 53 cross sections of the Gunung Kandu hill slopes. The slopes of Gunung Kandu were identified as class I (very good) to IV (poor). The kinematic analysis showed that 12 out of 53 hill slopes of Gunung Kandu were identified as having potential wedge, planar and toppling failures. The assessment showed that the stability of the western flanks can be classified as stable to unstable with the probability of failure from 0.2 to 0.6. The stability of the eastern and southern flanks range from very stable to partially stable with the probability of failure from 0.0 to 0.4. While the stability of northern flanks are from very stable to stable with the probability of failure of 0.0 - 0.2. This systematic approach offers a practical method especially for large area of rock slope stability assessment and the results from probability of failure values will help engineers to design adequate mitigation measures.