Rock Slope Stability Analysis Research Articles

Rock slope stability analysis of a limestone quarry in a case study of a National Cement Factory in Eastern Ethiopia

Rock slope failures pose significant challenges in geotechnical engineering due to the intricate nature of rock masses, discontinuities, and various destabilizing factors during and after excavation. In mining industries, such as national cement factories, multi-benched excavation systems are commonly used for quarrying. However, cut slopes are often designed with steep angles to maximize economic benefits, inadvertently neglecting critical slope stability issues. This oversight can lead to slope instability, endangering human lives and property. This study focuses on analyzing the stability of existing quarry cut slopes, estimating their final depth, and conducting a parametric study of geometric profiles including bench height, width, face angle, and rump width. Kinematic analysis helps identify potential failure modes. The results reveal that the existing quarry cut slope is prone to toppling, wedge failure, and planar failure with probabilities of 42.68%, 19.53%, and 14.23%, respectively. Numerical modeling using the finite element method (Phase2 8.0 software) was performed under both static and dynamic loading conditions. The shear reduction factor (SRF) of the existing quarry cut slope was 1.01 under static loading and 0.86 under dynamic loading. Similarly, for the estimated depth, the SRF was 0.82 under static loading and 0.7 under dynamic loading. These values indicate that the slope stability falls significantly below the minimum acceptable SRF, rendering it unstable. The parametric study highlights the face angle of the bench as the most influential parameter in slope stability. By adjusting the bench face angle from 90° to 75°, 70°, and 65°, the SRF increased by 31.6%, 35.4%, and 37.9%, respectively. Among these, a 70° bench face angle is recommended for optimal stability with a SRF of 1.27 under static loading and 1.18 under dynamic loading.

Stability analysis of rock slopes containing faults during excavation using microseismic monitoring and numerical simulation

Stability analysis of rock slopes containing faults during excavation using microseismic monitoring and numerical simulation

Rainfall-induced Landslide in the Lesser Himalaya: A Case Study of the Pallotari Landslide, Lamjung, Central-West Nepal

The Pallotari area, located in the Marsyangdi Rural Municipality, Lamjung, central-west Nepal, within the Lesser Himalaya, was impacted by a series of rainfall-induced landslides in July 2020. This study focuses on the Pallotari landslide, one of the major landslides in the area. Geological and engineering geological studies were performed to identify the causes of this landslide, and its impacts to the local community. Our results indicate the major causative factors to be intensive rainfall, steep topography with loose colluvial soil, and some anthropogenic activities such as the construction of the rural roads through the crown area. The study area still has hanging colluvial material on the crown as well as on the left flank of the landslide, and the numerical model for slope stability analysis indicates it to be unstable even in the unsaturated condition. The colluvial material in the middle portion of the landslide also has the risk of failure in the saturation condition which can be due to intensive rainfall. However, the rock slope stability analysis using the kinematic analysis does not show any contribution to the orientation of discontinuities on the slope failure. The presence of several transverse and longitudinal cracks in the surrounding of the landslide are signs of future failure.

Stability and reliability analysis of rock slope based on parameter conditioned random field

Stability and reliability analysis of rock slope based on parameter conditioned random field

Stochastic Rock Slope Stability Analysis: Open Pit Case Study with Adjacent Block Caving

In last decades, numerical modelling become a useful tool for solving complex geoengineering problems such as slope stability. On the other hand, probabilistic slope stability analyses are able to consider the variability of the rock mass properties in the decision making process. However, the application of probabilistic slope stability analysis with large three-dimensional numerical models is still limited due to the computational expenses of evaluating a substantial number of considered models. It is well-known that response surface methodology (RSM) couples the mathematical and statistical techniques to relate input variables to the response, allowing a reliable outcome and reasonable time of the analysis. Taking these advantages, this article presents an application of RSM in probabilistic slope stability analysis using three dimensional distinct element modelling. For this purpose, the most influencing factors including: uniaxial compressive strength, geological strength index (GSI), and shear strength of discontinuities, were taken into consideration to determine the probability of failure of an open pit slope located in vicinity of a block caving-induced subsidence crater. Numerical analysis of slope stability was conducted for an open pit slope using the Distinct Element Method code-3DEC. Probability distribution of the factor of safety (FS) was determined and possible slope failure mechanism was observed. In addition, the block caving-induced subsidence was investigated. The final outcomes indicate that Response Surface Methodology is applicable when couples with numerical modelling of complex issues, GSI is considered the most influential variable. The studied slope is considered stable due to the low value of the FS probability distribution (2.2%). This research is expected to provide a reference for slope stability analysis in case of transition from Open Pit to Underground Mining.

Study on the differences between Hoek–Brown parameters and equivalent Mohr–Coulomb parameters in the calculation slope critical acceleration and permanent displacement

Mohr–Coulomb (MC) strength criterion has been widely used in many classical analytical expressions and numerical modeling due to its simple physical calculation, but the MC criterion is not suitable for describing the failure envelope of rock masses. In order to directly apply MC parameters to analytical expressions or numerical modeling in rock slope stability analysis, scholars established a criterion for converting Hoek–Brown (HB) parameters to equivalent MC parameters. However, the consistency of HB parameters and equivalent MC parameters in calculating critical acceleration of slope needs to be further explored and confirmed. Therefore, HB parameters are converted into equivalent MC parameters by considering the influence of slope angle (1# case and 2# case when slope angle is not considered and slope angle is considered respectively). Then, the lower-bound of finite element limit analysis is used for numerical modeling, and the results of calculating critical acceleration using HB parameters and equivalent MC parameters are compared, and the influence of related parameters on the calculation of critical acceleration is studied. Finally, the influence of different critical accelerations on the calculation of slope permanent displacement is further analyzed through numerical cases and engineering examples. The results show that: (1) In the 1# case, the critical acceleration obtained by the equivalent MC parameters are significantly larger than that obtained by the 2 #case and the HB parameters, and this difference becomes more obvious with the increase of slope angle. The critical acceleration obtained by the 2# case is very close to the HB parameters; (2) In the 1# case, slope height is inversely proportional to ΔAc (HB(Ac) − 1#(Ac)), and with the increase of slope height, ΔAc decreases, while in the 2# case, the difference of ΔAc (HB(Ac) − 2#(Ac)) is not significant; (3) In the 1# case, the sensitivity of the HB parameters to ΔAc is D > GSI > mi > σci, but in the 2# case, there is no sensitivity-related regularity; (4) The application of HB parameters and equivalent MC parameters in slope permanent displacement is studied through numerical cases and engineering examples, and the limitations of equivalent MC parameters in rock slope stability evaluation are revealed.

Progressive failure and quantitative stability analysis of rock slope with cross-type discrete fracture network using spring-based smoothed particle hydrodynamics method

The propagation and coalescence of discontinuous cross-type joints are often the primary drivers of rock slope failures. Due to the inherent randomness of these joints, identifying suitable methods to accurately characterize progressive failure and quantitatively assess the stability of slopes with cross-type joints is particularly challenging. To address this, a Discrete Fracture Network-Spring Based-Smoothed Particle Hydrodynamics (DFN-SB-SPH) method is proposed, which considers cross-type DFN generation, rock matrix heterogeneity, cracking, block contact, and deposition within a unified SPH framework. In this approach, damage and contact of blocks are achieved by introducing a fracture sign to enhance the kernel function and applying Newton's law to the damaged particles to realize the point to point contact. A uniaxial compression test on rock samples with double fissures is carried out to verify the accuracy of the proposed method. The influence of joint density, geometric parameters (i.e., trace length, dominate dip angle) of cross joints, and rock mass heterogeneity on the failure characteristics of RSCD are investigated. The results revealed that the DFN-SB-SPH model possesses robust capabilities for crack tracking, mass movement, and contact slipping along fracture surfaces. Moreover, DFN generation, heterogeneous characterization, shear and tensile fractures within a single SPH framework without mesh distortion are realized. Five typical failure modes calculated by DFN-SB-SPH are primarily determined by the combination of joint dip angles and trace lengths. Furthermore, the dip angle, trace length, joint density, and rock mass heterogeneity significantly alter the stability of RSCD with sensitivity coefficients for factor safety of 27.7 %, 44.6 %, 72.9 % and 35.0 %, respectively. Higher dominant dip angles (above 60°) lead to significantly longer run-out distances for RSCD compared to lower angles (below 30°) once instability occurs. The sudden rise in major principal stress at the slope's top and toe, along with the shift of tensile stress concentration towards the middle, predicts the stages of crack propagation and sliding in slope failure.

Pseudo-dynamic viscoelastic stability analysis of anti-dip bedding rock slopes

Earthquakes contribute to the failure of anti-dip bedding rock slopes (ABRSs) in seismically active regions. The pseudo-static method is commonly employed to assess the ABRSs stability. However, simplifying seismic effects as static loads often underestimates rock slope stability. The development of a practical stability analysis approach for ABRSs, particularly in slope engineering design, is imperative. This study proposes a stability evaluation model for ABRSs, incorporating the viscoelastic properties of rock, to quantitatively assess the safety factor and failure surface under seismic conditions. The mathematical description of the pseudo-dynamic method, derived in this study, accounts for the viscoelastic properties of ABRSs and integrates the Hoek–Brown failure criterion with the Kelvin-Voigt stress-strain relationship of rocks. Furthermore, to address concurrent translation-rotation failure in ABRSs, upper bound limit analysis is utilized to quantify the safety factor. Through a comparison with existing literature, the proposed method considers the effect of harmonic vibration on the stability of ABRSs. The obtained safety factor is lower than that of the quasi-static method, with the resulting percentage change exceeding 5%. The critical failure surface demonstrates superior positional accuracy compared to the Aydan and Adhikary basal planes, with minimal error observed between the physical model test and the numerical simulation test. The parameter sensitivity analysis reveals that the inclination of ABRSs exhibits the highest sensitivity (Sk) value across the three levels of horizontal seismic coefficient (kh). The study aims to devise an expeditious calculation approach for assessing the stability of ABRSs during seismic events, intending to offer theoretical guidance for their stability analysis.

Rock Mass Characterization and Slope Stability Analysis Inlet Portal of Jragung Dam Diversion Tunnel, Indonesia

Abstract Slope stability is a serious problem that academics are still looking into in terms of human safety, equipment, and structures along the slope. Failure on slopes happens for a variety of reasons, including rock physical and mechanical properties, discontinuity factors, slope geometry, and external variables like as rainfall and seismic activity. The research location was conducted on the Jragung dam diversion tunnel, administratively located in Candirejo village, Pringapus sub-district, Semarang, Central Java Province. The purpose of this study was to use an empirical and numerical method to investigate the impact of rock mass categorisation on slope stability. The RMR (Rock mass rating) method is used to characterize rock mass, and the SMR (Slope mass rating) method is used to measure slope stability. The numerical slope stability analyses were carried out with the help of Phase2 (Rocscience, Inc.). The results showed that the slope at the intake portal was class IV (poor), and that it was unstable utilizing the SMR technique. According to numerical research, the basic design cut slopes with a 51° inclination were found to be unstable even after strengthening. It was suggested that the slope geometry and support measures be adjusted even more. Modified cut slopes were found to be stable after the slope inclinations were changed from 51° to 27° and shotcrete and rock bolt reinforcement were added.

Determination of Critical Slip Surface in Loose Rock Slope Stability Analysis

Determination of Critical Slip Surface in Loose Rock Slope Stability Analysis

Study of slope stability analysis method based on equivalent Mohr‐Coulomb strength parameters of three‐dimensional stress state

AbstractMost rock slope stability analysis methods are based on the Hoke–Brown criterion under a two‐dimensional state of stress, which somewhat ignores the effect of intermediate principal stress. In this paper, by introducing the improved three‐dimensional H‐B criterion into the Meridian plane, the tangent line of a point on the H‐B strength envelope is regarded as its instantaneous equivalent M‐C parameter. Based on this, a formula for solving the equivalent M‐C strength parameters under a three‐dimensional stress state is established to describe the shear strength parameters of rock mass, considering different stress states. Taking three kinds of rocks as examples, the influence of the intermediate principal stress on their strength parameters is analyzed. On this basis, the realization scheme of the nonlinear strength reduction method is established, the stability of the slope is studied, and an example verifies the feasibility of this method. This method fully considers the nonlinear characteristics of rock slope strength parameters under a three‐dimensional stress state and provides a solid basis for slope stability analysis.

Enhanced Rock Slope Stability Analysis: Integrating the Partial Factor Method into the Limit Equilibrium Method

Rock slope stability is crucial for sustainable design. Especially concerning natural or artificial rock-cut slopes. The stability of these slopes depends largely on features of rock mass, particularly discontinuities. Failure modes are determined by these features and are evaluated using kinematics analysis with stereographic projections. Various methods exist for analyzing rock slopes, including the limit equilibrium method (LEM), which assesses stability based on a factor of safety (FS). Conversely, the partial factor method (PFM), predominantly used in Europe, offers a more reliable and probabilistic approach, incorporating uncertainty factors. Although Eurocode, which employs the PFM, is widely utilized, it faces disputes and undergoes updates based on ISRM recommendations. The partial factor method is considered more conservative than the limit equilibrium method due to its comprehensive probabilistic approach. The choice between methods depends on project requirements, data availability, and expertise. This study compares the limit equilibrium and partial factor methods for rock slope analysis, concluding that the partial factor method is more conservative and sustainable for long-term stability assessment. Whereas, the traditional method is often used for short-term assessments.

Stability Analysis of Jointed Rock Slopes Based on the Universal Elliptical Disc Model

A discrete fracture network (DFN) represents the random distribution of fractures within rock masses in three dimensions and has been widely used in the stability analysis of jointed rock slopes. This study introduces a novel method for constructing three-dimensional DFN models to address the limitations of traditional circular or polygon-based models. This method employs the universal elliptical disc (UED) model, combined with the discrete element method (DEM) in 3DEC, for the probabilistic analysis of jointed rock slope stability. The paper begins with an explanation of the fundamental principles of the UED model, and continues to detail the procedures for creating a three-dimensional DFN using the UED model and for analyzing slope stability using the DEM. An open-pit mine rock slope in the USA serves as a case study to illustrate the application of the proposed method. This approach facilitates the integration of the UED model into 3DEC and offers a more realistic depiction of the three-dimensional DFN, which enhances both the accuracy and efficiency of stability analysis in jointed rock slopes.

Rock Slope Stability Analysis Using Terrestrial Photogrammetry and Virtual Reality on Ignimbritic Deposits.

Puerto de Cajas serves as a vital high-altitude passage in Ecuador, connecting the coastal region to the city of Cuenca. The stability of this rocky massif is carefully managed through the assessment of blocks and discontinuities, ensuring safe travel. This study presents a novel approach, employing rapid and cost-effective methods to evaluate an unexplored area within the protected expanse of Cajas. Using terrestrial photogrammetry and strategically positioned geomechanical stations along the slopes, we generated a detailed point cloud capturing elusive terrain features. We have used terrestrial photogrammetry for digitalization of the slope. Validation of the collected data was achieved by comparing directional data from Cloud Compare software with manual readings using a digital compass integrated in a phone at control points. The analysis encompasses three slopes, employing the SMR, Q-slope, and kinematic methodologies. Results from the SMR system closely align with kinematic analysis, indicating satisfactory slope quality. Nonetheless, continued vigilance in stability control remains imperative for ensuring road safety and preserving the site's integrity. Moreover, this research lays the groundwork for the creation of a publicly accessible 3D repository, enhancing visualization capabilities through Google Virtual Reality. This initiative not only aids in replicating the findings but also facilitates access to an augmented reality environment, thereby fostering collaborative research endeavors.

Rock slope stability analysis under Hoek–Brown failure criterion with different flow rules

The stability analysis of homogeneous rock slope following the Hoek–Brown failure criterion under the hypothesis of different flow rules is performed based on limit equilibrium and finite element methods. The applied failure criterion is the generalized Hoek–Brown that can be introduced as a shear/normal function in analysis applying different flow rules. The results are compared with those obtained by the application of equivalent shear strength parameters of the Mohr–Coulomb criterion, considering that this is still the most widely used criterion in rock slope stability analysis and is still the base for the shear strength reduction method applied in finite element modelling. Different proposals for estimating the equivalent strength parameters based on confining stress level are evaluated. The limitation of stress-dependent linear Mohr–Coulomb parameters is emphasized by analysing the vertical cut problem, for which, depending on the chosen stress level, different critical heights are obtained for the same material. Sensitivity analysis of geotechnical parameters used as input for failure criterion is performed to determine their influence on slope stability. Probabilistic analysis is conducted to determine the probability of failure when different flow rules are applied. If slope stability analysis is performed with an assumption of associative flow rule, the probability of failure is within the acceptable limits for the considered case study, while employing non-associative flow rule, the probability of failure is rather high. The chart is presented that could be readily used to estimate the combination of σci, GSI, and mi values that produce failure for the analysed case study.

Importance of Field Observations for the Numerical Stability Analysis of Rock Slopes: Case Studies from the Sikkim Himalaya

Importance of Field Observations for the Numerical Stability Analysis of Rock Slopes: Case Studies from the Sikkim Himalaya

Step-path failure mechanism and stability analysis of water-bearing rock slopes based on particle flow simulation

Step-path failure is a typical damage mode of rock slope featuring intermittent joints. In order to investigate the effect of water-fracture interaction on the stepped failure, laboratory experiments of rock materials and numerical simulation of slopes with intermittent joints were conducted. At the laboratory scale, the influence of water-fracture interaction on the mechanical characteristics and acoustic emission response of step-path failure in rocks was examined, and the particle flow model parameters were calibrated for uniaxial testing. At the field scale, the step-path failure process of the rock slope near Longmenqiao reservoir was numerically analyzed using the particle flow method to assess the effects of water and joint distribution on failure. Laboratory findings suggest that compared with dry red sandstone, the average uniaxial compressive strength and average elastic modulus of saturated red sandstone decrease by 35.82% and 23.33%, respectively. The increase in fissure angle in sandstone results in enhanced strength and stiffness, alongside a transition from shear to tension failure mode, with a delayed occurrence of large-scale acoustic emission events. In particular, within the 30°–60° range, the uniaxial compressive strength and elastic modulus of saturated sandstone increase by 66.78% and 29.64%, respectively. The analysis of crack propagation and stress field during slope deformation shows that step-path failure is a progressive process from bottom to top, and revealed the control mechanism of joint and bridge angle on slope stability. The research results enhance the understanding of the step-path failure mechanism and provide important theoretical support for the stability evaluation and landslide monitoring of rock slopes with intermittent joints.

Stability analysis for rock slope using finite element modeling near Darekasa Railway Station: A case study

Stability analysis for rock slope using finite element modeling near Darekasa Railway Station: A case study

Influence of Hydraulic Distribution Pattern on the Rock Slope Stability under Block Toppling Failure

In this paper, an analytical model for the stability analysis of rock slope subjected to block toppling pertaining to different hydraulic forms has been developed. In the traditional analytical model, ground water pressure is considered to be varied hydrostatically. To better reflect the physical situation, three different hydraulics forms have been considered in developing a stability model for a rock slope susceptible to block toppling. It is well known fact that presence of ground water causes the instability in a rock slope. The present study observes that hydraulic distribution forms also significantly influence the stability of the rock slope. Ground water pressure markedly increases the toppling forces on the blocks and reduces the normal and shear force at the base of block along failure plane, thereby causing instability. The increase in toppling force and reduction in the factor of safety on the blocks are more prominent when the flow slit is blocked, indicating a condition of permanent or seasonal frozen strata. The study highlights that adopting the traditional hydraulic form to analyse block toppling stability, considering presence of ground water would not be suitable for all field conditions. This necessitates the selection of an appropriate hydraulic distribution form based on the encountered field conditions.

Risk assessment in a rock slope stability analysis using a Mamdani fuzzy controller

Risk assessment in a rock slope stability analysis using a Mamdani fuzzy controller