Slope Stability Evaluation Research Articles

Study on the Influence of Seismic Wave Parameters on the Dynamic Response of Anti-Dip Bedding Rock Slopes under Three-Dimensional Conditions

As a result of earthquakes, the deformation and failure caused by anti-dip bedding rock slopes are large, and their seismic dynamic response law is complex. Using the three-dimensional discrete element numerical analysis software 3DEC, the influence of seismic wave parameters on the dynamic response of anti-dip bedding rock slopes was systematically studied, with special focus on the influence of the angle between seismic wave incidence direction and slope trend on the dynamic response of anti-dip bedding rock slopes under three-dimensional conditions. The orthogonal test was designed to conduct sensitivity analysis of five seismic parameters, including seismic wave amplitude, incidence angle of the S-wave, frequency, duration, and the time difference between the P-wave’s and the S-wave’s peak. The results revealed that the S-wave’s amplitude As and the holding time T of the seismic wave are positively correlated with the acceleration amplification factor of the slope, and the incident direction γ of the S-wave is negatively correlated with the acceleration amplification factor of the slope. The increase of seismic wave frequency f and the time difference Δt between the P-wave’s and the S-wave’s peak lead to the first increase and then decrease of the Y-directional displacement of the slope. The sensitivity of each seismic wave parameter to the Y-directional acceleration amplification factor at the shoulder of anti-dip bedding rock slopes in earthquake conditions is ordered as follows: S-wave’s amplitude As > frequency f > S-wave’s incidence angle γ > the time difference Δt > holding time T. the study results provide reference and basis for stability evaluation and engineering design of anti-dip bedding rock slopes in areas with high seismic intensity.

Numerical Analysis of an Explicit Smoothed Particle Finite Element Method on Shallow Vegetated Slope Stability with Different Root Architectures

Planting vegetation is an environmentally friendly method for reducing landslides. Current vegetated slope analysis fails to consider the influence of different root architectures, and the accuracy and effectiveness of the numerical simulations need to be improved. In this study, an explicit smoothed particle finite element method (eSPFEM) was used to evaluate slope stability under the influence of vegetation roots. The Mohr–Coulomb constitutive model was extended by incorporating apparent root cohesion into the shear strength of the soil. The slope factors of safety (FOS) of four root architectures (uniform, triangular, parabolic, and exponential) for various planting distances, root depths, slope angles, and planting locations were calculated using the shear strength reduction technique with a kinetic energy-based criterion. The results indicated that the higher the planting density, the stronger the reinforcement effect of the roots on the slope. With increasing root depth, the FOS value first decreased and then increased. The FOS value decreased with an increase in slope angle. Planting on the entire ground surface had the best improvement effect on the slope stability, followed by planting vegetation with a uniform root architecture in the upper slope region or planting vegetation with triangular or exponential root architecture on the slope’s toe. Our findings are expected to deepen our understanding of the contributions of different root architectures to vegetated slope protection and guide the selection of vegetation species and planting locations.

Slope Mass Rating (SMR) Classification for Rock Slope Stability and Geohazard Vulnerability Assessment

Quantitative classification from the Slope Mass Rating (SMR) has introduced an empirical assessment for rock slope stability rating. This stability classification enables us to foreseethe magnitude and susceptibility of rock mass failure towards adjacent infrastructure and human life. In this study, the stability of quarry rock slope was classified using SMR classification system and kinematic stability analysis before being correlatedwith geohazard vulnerability assessment. Geological formation study with site geographical survey from aerial photogrammetry technique provided comprehensive data for the study area. Fieldwork to evaluate the SMR assessment parameters was conducted by discontinuity mapping using scanline method. In-situ evaluation of rock mass such as rebound surface hardness and discontinuity characterization was carried out with rock material sampling for laboratory testing. Kinematic stability analysis presented an estimation for the direction and mode of rock slope failure. The SMR classification that constitutes geomechanics attributes had introduced the global stability rating of rock mass structure, thus facilitating the prediction of potential failure magnitude. Hence, the integration of these stability indications provides sufficient empiricalestimation for geohazard vulnerability zoning for the studied area.

NURBS Surface-Altering Optimization for Identifying Critical Slip Surfaces in 3D Slopes

The evaluation of slope stability of a three-dimensional slope requires identifying the critical slip surface with the minimum factor of safety, which is a complex optimization problem. Failure to identify the critical slip surface can lead to unconservative conclusions about the stability of a slope. This paper proposes a novel 3D surface-altering optimization method, which iteratively alters the geometry of a 3D slip surface to find the critical slip surface representing the minimum factor of safety in a slope. The geometry of the slip surface is defined via nonuniform rational basis spline (NURBS) curves formed over a plan grid of control points. The proposed method includes a series of five subroutines that apply various forms of transformations to the control points. These subroutines include minimization problems, which determine the optimal transformation parameters for minimizing the obtained factor of safety of the resulting slip surfaces. Given that any geometrically defined slip surface can be approximated using an equivalent series of NURBS control points, the proposed method can be used in efforts to further reduce the global factor of safety first obtained via conventional search methods, such as those involving spherical or ellipsoidal slip surfaces. To demonstrate its effectiveness, the proposed method was applied to further optimize the critical ellipsoidal slip surfaces reported in some numerical examples. Comparing the results with those limited to ellipsoidal slip surfaces, the proposed method was consistently able to identify slip surfaces with significantly lower factors of safety. The postaltered slip surfaces also matched closely with finite element shear strength reduction results. As such, the proposed method is effective in searching for critical slip surfaces and can be used as a final step in the critical surface searching routine.

Performance Evaluation and Engineering Verification of Machine Learning Based Prediction Models for Slope Stability

Stability evaluation of geotechnical engineering slopes is of great significance for the risk control and safe operation of many engineering. Machine learning methods can effectively establish the potential relationship between geological features and slope behavior under complex environments, to accurately evaluate the stability of slope rock and soil. This work investigated the performance of eight commonly used machine learning models to predict slope safety factors. First, the prediction system of slope safety factors based on machine learning was established by combining historical data of slopes for parameter optimization and cross-validation. Then, four accuracy evaluation indexes, MSE, RMSE, MAE, and Pearson correlation, were objectively weighted, and objective weighting-TOPSIS models were constructed to comprehensively quantify the performance of each model. Finally, the best machine learning model was used in the slope stability analysis of the Sino–Russian natural gas control section. The research results show that there are obvious differences in the prediction accuracy of the slope safety factor among different models. The ANN model has the highest evaluation accuracy, and the ensemble learning method performs well in the data set. The machine learning model can better predict the safety factor of the slope under different working conditions. The discrepancies with the numerical simulation results are related to the limitations of data sets and the differences in analysis methods. The analysis method of this study not only provides a new research idea and solution for the construction and evaluation of the model predicting slope safety factors, but also applies to other geotechnical engineering instability problems.

Earth slope stability evaluation subjected to earthquake loading using chaotic sperm swarm optimization

Earth slope stability evaluation subjected to earthquake loading using chaotic sperm swarm optimization

Prediction and Analysis of Slope Stability Based on IPSO-SVM Machine Learning Model

In the evaluation and prediction of slope stability, the traditional numerical analysis method, which is over reliant on experience, takes a large amount of computing time and lacks the ability to reflect the fuzzy and nonlinear characteristics of slope parameters well. Considering the above characteristics, this study proposes an improved particle swarm optimization of support vector machine (IPSO-SVM) algorithm model, which combines optimized particle swarm optimization (IPSO) and support vector machine (SVM) and applies it to slope stability prediction. Based on 28 groups of slope engineering data, the stability prediction results of IPSO-SVM, PSO-SVM, and SVM models were compared with real values for analysis. The results show that the maximum relative error of the IPSO-SVM model is only 1.3%, and the average relative error is 1.1%, which is far lower than the prediction error of the PSO-SVM model and SVM model; therefore, the prediction result of IPSO-SVM is the closest to the real value. This method can accurately predict the slope safety factor under the influence of different indexes, and the research results can provide guidance for practical engineering.

Dynamic variations of interception loss-infiltration-runoff in three land-use types and their influence on slope stability: An example from the eastern margin of the Tibetan Plateau

Hydrological processes in slopes play an important role in the evaluation of slope stability at the catchment scale. This study investigated the dynamic variations of interception loss-infiltration-runoff in three land-use types (bare slope and slopes with C. dactylon and I. amblyantha cover) for incident rainfall and their influence on slope stability. Gross rainfall, surface runoff, and subsurface flow were measured during the rainy season in 2020, and the influences of rainfall characteristics (rainfall amount and intensity) and slope gradients on canopy interception loss, water infiltration, and surface runoff were evaluated. On this basis, a model considering infiltration zonation was adopted to estimate slope stability under the influence of infiltration modified by vegetation. Field test results showed that runoff on bare slope generally occurred following rainfall events with amounts of > 6.1 mm or intensities of > 7.2 mm h−1. For slopes covered by C. dactylon and I. amblyantha, the thresholds of rainfall intensity for runoff generation were 25 mm h−1 and 36 mm h−1, respectively. The calculated relative interception loss for the slope with C. dactylon cover stabilized at 0.05–0.10 when the rainfall amount was > 18 mm, while that for the slope with I. amblyantha cover stabilized at 0.10–0.15 when the rainfall amount was > 30 mm. Moreover, the slope with C. dactylon cover appeared to have a higher proportion of infiltration than that with I. amblyantha cover. The stable infiltration rate in the three land-use types decreased gradually with increasing slope gradient, whereas an opposite pattern was exhibited for the stable runoff intensity. The influence of the morphological features of plant species on the variation of interception loss-infiltration-runoff weakened as slope gradient increased. The modeling results demonstrated that the depth of the wetting front was negatively correlated with slope gradient and followed a quadratic function with rainfall intensity. Based on the computed safety factor at the wetting front, the critical times of slope instability follow the order of bare slope (46.2 min) > I. amblyantha slope (34.8 min) > C. dactylon slope (30.5 min). The modification of infiltration by plants accelerated slope instability, with potential reductions in the safety factor by 15.9%–53.1%. Slope gradient plays a dominant role in slope stability, and the influence of modified infiltration on slope stability weakens with increasing slope gradient. Those findings provide valuable information for the decision makers concerned with planting I. amblyantha in the subtropical region to reduce peak flood discharge and prevent slope instability.

Stability evaluation of finite soil slope in front of piles in landslide with displacement-based method

Stability evaluation of finite soil slope in front of piles in landslide with displacement-based method

Stability Evaluation of Diversion Tunnel Portal Slopes at Lau Simeme Dam Site, Indonesia, using Limit Equilibrium Method

Construction of the Lau Simeme Dam used a tunnel as a diversion channel. Slopes at the diversion tunnel portals were prone to failure due to the tunnel excavation and earthquake. Earthquake load was not considered in the designs of the inlet and outlet portal slopes. This research evaluated stability of the tunnel portal slopes under static and earthquake loads using limit equilibrium methods of the Bishop Simplified and Morgenstern-Price. Input material properties for the slope stability analyses were obtained from evaluations of soil and rock cores, including determination of lithology type and rock mass quality based on Geology Strength Index (GSI), and laboratory testing. Evaluations of soil and rock cores indicated that the inlet portal slope consisted of residual soil, good quality tuff breccia, and good quality sandstone. The outlet portal slope consisted of residual soil, poor quality sandstone, poor quality tuff breccia, fair quality sandstone, fair quality tuff breccia, and good quality tuff breccia. The earthquake load coefficient determined by the seismic analyses based on the peak ground acceleration map for 10% probability exceedance in 50 year was 0.125 g. The slope stability analyses showed that the designed inlet and outlet portal slopes were stable under static and earthquake loads. The Bishop Simplified and Morgenstern-Price resulted in relatively similar Fs values. The Fs values of the inlet and outlet portal slopes decreased with the earthquake load application. Although Fs values of the outlet slope under static and earthquake loads met the requirements specified by SNI 8460:2017, the rock mass conditions, particularly the poor rock masses of layers 2 and 3, required special attention. Application of slope reinforcement methods, such as shotcrete, is suggested to further increase the slope stability.

An Overview of Slope Failure in Mining Operations

The primary aim of every twenty-first century mining operation is to extract as much ore as possible in a safe and economical manner. Failure in mine excavation occurs when the shear stress acting on the rock is greater than the shear strength of the rock mass. The stability of rock slopes in open-pit mine and quarry operations is extremely important from both economic and safety points of view because unstable slopes can result in the loss of human life and damage to properties. This paper presents an overview of several case studies of slope failure in mining operations and explains various modes of failure in rock slopes, as well as factors that influence the stability of slope walls. With the aim of enforcing the importance of monitoring and evaluating slope stability in mining, both linear equilibrium and numerical modeling techniques were reviewed to elaborate their importance in designing stable slopes. In addition, the process of slope failure was discussed, and key signs of failure were indicated. In an effort to prevent mines from experiencing the hazards of slope failure, this study reports previous work performed in determining slope failure and the current state-of-the-art models, which entail the integration of analytical methods with artificial intelligence techniques. This innovation would help overcome the drawbacks of conventional prediction techniques that are cumbersome and ambiguous.

Evaluation of 3D slope stability based on the minimum potential energy principle

Based on the minimum potential energy principle, a novel method is proposed to determine the global sliding direction (GSD), the critical slip surface and the corresponding safety factor (SF) of three-dimensional (3D) slopes with arbitrary-shaped slip surface. The resistance direction at one point on the failure surface is determined based on the relationship between the mobilized shear strength and the virtual displacement which minimizes the total potential energy of failure mass system. The GSD is considered to be the opposite to the composition of resistance on failure surface. Meanwhile, the critical slip surface of 3D slope is generated by two random curves with 8 parameters. Three benchmark slopes and a slope from practice engineering are analyzed to test the validity and accuracy of the present model. The results from the developed method match well with the classical solutions, and the obtained SFs demonstrate that some factors (e.g., local surcharge, composite failure surface, slope geometry and so on) can cause slope instability and failure. The location of critical slip surface and the SF provided by the present method are in good agreement with other solutions. Finally, the influence of failure body volume, shear strength parameters, unit weight, slope angle, surcharge and slope height on the GSD is revealed. This study provides a useful guideline for landslide prediction and reinforcement management in slope engineering.

Cloud Model Membership Degree of Rock Slope Stability Evaluation: Method and a Case Study

Cloud Model Membership Degree of Rock Slope Stability Evaluation: Method and a Case Study

SVNN-ANFIS approach for stability evaluation of open-pit mine slopes

The stability of the open-pit mine slope has an important impact on the safe operation and benefits of the mining company. This paper proposes a single-valued neutrosophic number-based adaptive neuro fuzzy inference system (SVNN-ANFIS) approach to evaluate the open-pit mine slope stability. In the method, it utilizes the single-valued neutrosophic number concept for expressing the truth, indeterminate, and falsity information of influencing factors/indices (slope height, slope angle, potential slip plane angle, cohesion, internal friction angle and rock density) of the open-pit mine slope stability by truth, indeterminate, and falsity membership functions. Then, three ANFISs are used to obtain the corresponding relations between the influencing factors and the slope stability in truth, indeterminate, and falsity situations. Finally, the truth, indeterminate, and falsity output of the three ANFISs, i.e., a SVNN output, whose score value can be used to evaluate the slope stability through a score function of SVNN. The application results of the proposed approach have reflected that the training accuracy reaches 99.20% and the testing accuracy reaches 97.62%. Therefore, the established SVNN-ANFIS method provides a new effective way for evaluating open-pit mine slope stability in the uncertain environment.

Evaluation of slope stability and displacement by Energy-based Newmark method using earthquake energy: A research note

Evaluation of slope stability and displacement by Energy-based Newmark method using earthquake energy: A research note

Characterization and quantitative evaluation of preferential infiltration in loess, based on a soil column field test

Preferential infiltration occurs widely in loess deposits and has a major impact on water movement and redistribution. However, preferential infiltration is a complex process, and previous research has focused principally on its qualitative description. Few studies have carried out infiltration tests to assess preferential infiltration in loess. In this study we conducted five soil column infiltration field tests in the Heifangtai area of Gansu Province, China, to explore preferential infiltration processes and the characteristics of loess. Based on the test data, the preferential infiltration is qualitatively assessed, and a quantitative calculation method for the preferential infiltration of loess with vertical cracks is proposed. The following conclusions were drawn: 1) The relationship between the infiltration rate of loess and the reciprocal of wetting front depth is a positive linear relationship under homogeneous infiltration, but non-linear under preferential infiltration. 2) The degree of preferential infiltration can be determined based on the distance of data points to the infiltration rate-wetting front propagation velocity gradient under homogeneous infiltration. 3) Based on the principle of similarity of infiltration of adjacent soil, we calculate that the preferential infiltration rate of closed cracks is two to three orders of magnitude greater that the homogeneous infiltration rate, and that the contribution of stable preferential infiltration to the total infiltration is about 20%. Quantitative evaluations of preferential infiltration are helpful in calculating slope seepage, evaluating slope stability, and researching landslide initiation mechanisms.

Study on the Weakening Law and Classification of Rock Mass Damage under Blasting Conditions

To study the effects of declining mechanical parameters caused by blasting excavation on slopes, we introduced the damage degree index Ds, and established a relationship between Ds and the disturbance factor D in the Hoek–Brown criterion, along with a basic quality index BQ for the rock mass. We then explored the change law for the degree of rock damage Ds as a function of the disturbance factor D. We also used a phosphate mine slope in Guizhou Province for reference, and analyzed the process of damage evolution of the slope based on the RHT (Riedel-Hiermaier-Thoma Constitution) in LS-DYNA (Yunnan, China). Results showed a direct relationship between the GSI value in the Hoek–Brown criterion and the initial damage degree of the slope. As Ds increases, D increases exponentially. However, the compressive strength, elastic modulus, cohesion, and internal friction angle decreased nonlinearly, and the tensile strength of the rock mass decreased linearly. Among these parameters, the compressive strength decreased the most rapidly, while the internal friction angle decreased slowly. We also established a new grade for rock self-stabilization with Ds as the evaluation standard. Thus, these results may provide a theoretical basis for determining the mechanical properties of rocks for future slope protection and stability evaluations.

STABILITY ANALYSIS OF ROCK SLOPE USING SLOPE STABILITY PROBABILITY CLASSIFICATION (SSPC) METHOD IN PIYUNGAN-PATUK AREA, YOGYAKARTA SPECIAL REGION

Landslide events in an area are manifestations of unstable slope conditions so evaluation of slope stability and mapping of areas prone to landslides is very important as an effort to mitigate landslides. In this study, the Slope Stability Probability Classification (SSPC) method was used to evaluate slope stability in the Piyungan-Patuk area. which is a rock mass classification system for slope stability that classifies 3 (three) different rock masses through a three-step approach namely: Exposure Rock Mass (ERM), Reference Rock Mass (RRM), and Slope Rock Mass (SRM). Slope stability analysis results on 18 selected slopes obtained a probability of slope stability with very low to very high classification with a probability value of stability <0.5 to> 95, where the probability value is strongly influenced by rock mass parameters such as rock strength, discontinuity, and weathering rate.

Field and numerical studies to evaluate slope stability in municipal solid waste sites

Field and numerical studies to evaluate slope stability in municipal solid waste sites

Failure of Rock Slopes with Intermittent Joints: Failure Process and Stability Calculation Models

Abstract Rock slopes with intermittent joints in open-pit mines are complex geological bodies composed of intact rock and discontinuous structural planes, and their stability analysis are necessary for mine disaster prevention. In this study, a series of base friction tests were performed to determine the failure process and displacement field evolution of rock slopes with intermittent joints using the speckle technique of a noncontact measurement system. Next, stability calculation models of the slopes were established from the energy perspective using the plastic limit analysis theory, and the effects of the joint inclination angle and coalescence coefficient of rock bridges on the slope stability were evaluated. The four main conclusions are as follows: (1) The failure of rock slopes with intermittent joints shows the feature of collapse-lower traction-upper push. (2) Based on the failure modes of rock bridges in slopes, the failure of rock slopes with intermittent joints could be divided into three types: tensile coalescence (type A), shear coalescence (type B), and tensile–shear coalescence (type C). (3) Among the three slope types, the stability of the type A slope is significantly influenced by rock cohesion, whereas that of the type B slope is significantly influenced by joint cohesion. The stability of type C slope is significantly influenced by the joint inclination angle and joint friction angle. (4) The local-stable slope is unstable while the first through-tensile crack in the zone of the potential sliding body higher than the critical instability height appeared. This study guides the stability evaluation and instability prediction of jointed rock slopes in open-pit mines.