Evaluation Of Rock Slope Stability Research Articles

Fuzzy-Based Intelligent Model for Rapid Rock Slope Stability Analysis Using Qslope

Artificial intelligence (AI) applications have introduced transformative possibilities within geohazard analysis, particularly concerning the assessment of rock slope instabilities. This study delves into the amalgamation of AI and empirical techniques to attain highly precise outcomes in the evaluation of slope stability. Specifically, our primary objective is to propose innovative and efficient methods by investigating the integration of AI within the well-regarded Qslope system, renowned for its efficacy in analyzing rock slope stability. Given the complexities inherent in rock characteristics, particularly in coastal regions, the Qslope system necessitates adjustments and harmonization with other geomechanical methodologies. Uncertainties prevalent in rock engineering, compounded by water-related factors, warrant meticulous consideration during all calculations. To address these complexities, we present a novel approach through the infusion of fuzzy set theory into the Qslope classification, leveraging fuzziness to effectively quantify and accommodate uncertainties. Our approach employs a sophisticated fuzzy algorithm encompassing six inputs, three outputs, and 756 fuzzy rules, thereby enabling a robust assessment of rock slope stability in coastal regions. The implementation of this method capitalizes on the high-level programming language Python, enhancing computational efficiency. To validate the potency of our AI-based approach, we conducted preliminary tests on slope instabilities within coastal zones, indicating a promising initial direction. The results underwent thorough evaluation, affirming the precision and dependability of the proposed method. However, it is crucial to emphasize that this work represents a first attempt to apply AI to the evaluation of rock slope stability. Our findings underscore a high degree of concurrence and expeditious stability assessment, vital for timely and effective hazard mitigation. Nonetheless, we acknowledge that the reliability of this innovative method must be established through broader applications across diverse scenarios. The proposed AI-based approach’s effectiveness is validated through a preliminary survey on a slope instability case within a coastal region, and its potential merits must be substantiated through broader validation efforts.

Stability Evaluation of Rock Slopes with Cracks Using Limit Analysis

Stability Evaluation of Rock Slopes with Cracks Using Limit Analysis

Kinematic and Slope Mass Rating Application for Rock Slope Stability Evaluation Along Shanadar-Goratu Road in the Gali-Ashkafte Valley, Erbil, NE-Iraq

A Study of rock slope stability along the Shanadar-Goratu main road, which is located near Mergasur town, northeast of Erbil city, is very necessary because many many slope failures take place every year, especially in the wet season. It is the main road between Erbil city and many towns and villages in the Mergasur district. For the current research, eight (8) rock-cut slope stations have been selected for 4.5 kms along the road from Shanadar to Goratu, based on differences in discontinuity pattern, slope geometry, and failure types. Field data has been assessed by the kinematic method, through DIPS v7.0 software, and by slope mass rating classification system, through SMRTool - v205 software. Kinematic analysis from DIPS v7.0 software showed that three types of failures (planar, wedge and toppling failures) may occur, and the largest susceptible rock masses to failure are of slope stations no. 1,5 and 8. In the worst conditions, the discrete-SMR and continuous-SMR pointed out that slope stations no. 1, 5 and 7 are completely unstable (class V – very bad slopes) with a failure possibility of 90%, while slope stations no. 2, 3 and 4 are unstable (class IV – bad slope) with failure possibility of 60%. However, slope stations no. 6 and 8 are partially stable (class III – normal slope face) with failure possibility of 40%, with an exception for slope station no.6 which is unstable (class IV – bad slope face) from continuous-SMR.

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

Effect of Freeze-thaw Cycles on Microstructure and Mechanical Properties of Limestone

In studying the effect of freeze-thaw cycles on the microstructure and mechanical properties of limestone, scanning electron microscope, low-field nuclear magnetic resonance, and uniaxial compression tests are carried out on the limestone samples dried and subject to 5, 10, 15, and 20 freeze-thaw cycles. Through analysis and discussion, it was found that the number of freeze-thaw cycles has a significant effect on the microstructure of the limestone samples. Compared to the dry samples, the number of microcracks of the limestone samples subjected to freeze-thaw cycles is increased. Moreover, the crack width is positively correlated to the number of freeze-thaw cycles. With an increase in freeze-thaw cycles, the signal intensity of the T2 spectrum is considerably increased, and the connectivity of the micropores and fissures is increased. In addition, the peak compressive strength and elastic modulus showed a significant negative correlation with the number of freeze-thaw cycles. Again, compared to the dry samples, the peak compressive strength of the samples subject to 5, 10, 15, and 20 freeze-thaw cycles decreased by 14.7%, 22.0%, 28.7%, and 37.5%, respectively. The elastic modulus also decreased by 8.0%, 11.4%, 11.7%, and 21.5%, respectively. Therefore, these findings provide basic parameters for the stability evaluation of rock slopes in Northwest Guizhou.

Application of group decision-making AHP of confidence index and cloud model for rock slope stability evaluation

At present, the weights of most evaluation indexes in fuzzy analysis methods of rock slope are a fixed value. However, the influence of the evaluation indexes on slope stability actually remains uncertain and fuzzy. As a result, if only the fixed weights are employed, it will disagree with the reality. To overcome the current problem, the cloud model method was introduced in the paper. In addition, the analytic hierarchy process (AHP) method for group decision based on confidence indexes was proposed to construct the cloud model of weight. In the meanwhile, the evaluation indexes, grading standards, grading intervals and cloud model characteristic parameters were determined by referring to the recommended China's industry standards and the experiences of previous researchers. On this basis, an application program was developed using Python language. The application was applied in the stability evaluation of a rock slope in Donghu Town, Lianjiang County, Fujian Province, China. According to the results, the slope was generally stable, but very unstable in some local areas. The result was highly or basically consistent with the result of CSMR, FLAC, AHP-TOPSIS, FSMR, or Fuzzy-AHP method as well as the actual situation on site, confirming the effectiveness of this evaluation method.

Elastoplastic-damage-seepage coupling model and numerical algorithm for rock slope stability evaluation

The stability of slope under complex geological conditions is one of the essential issues in geotechnical engineering. The mechanical damage caused by external force load and the hydraulic property of rock have both significant influences on slope stability. However, the two factors and the coupling process between them are not considered in the traditional slope safety calculation method. Firstly, in this paper, an elastoplastic-damage-seepage coupling model is established based on the modified Mohr-Coulomb (M-C) criterion. This model takes into account the weakening effect of damage on the strength of rock mass. Further, according to the Biot's theory and the evolution equation of permeability coefficient, a complete hydraulic-mechanics (HM) coupling model is established. Secondly, the fully implicit backward Euler algorithm and "strict-cornered" algorithm are used to integrate the stress precisely. The complete coupling analysis of HM is implemented by the step-by-step iterative method. By combining the centrifugal loading method (CLM) with the FEM program, the factor of slope safety (FOS) under the coupling influence of damage-seepage can be solved. The calculation results showed that, compared with the traditional rounded M-C model, the results obtained by the "strict-cornered" algorithm method in this paper are closer to the theoretical solution. The solution process is robust with a global second-order convergence rate. After considering the effects of damage and seepage, the FOS is obviously reduced. Finally, the model is applied to the stability evaluation of an actual engineering. The variation rules of pore water pressure, displacement field, damage zone and FOS are calculated under different head heights. The model built in this paper considers the coupling characteristics of rock seepage-stress-damage well. The proposed numerical algorithm ensures the accuracy and rationality of the calculation results which provides a theoretical foundation for engineering application.

Rock slope stability evaluation using kinematic and kinetic methods along the Kamyaran-Marivan road, west of Iran

Interest in rock slope stability in mountainous regions has increased greatly in recent years. This issue has become a topic of major interest for geoscientists and engineering professionals, as well as for private citizens and local administrators, in many parts of the world. This paper evaluates the stability of seven rock slopes along the Kamyaran-Marivan tourist road, Kurdistan province, Iran, using various methods. The two main reasons for performing this research were to determine whether different methods of stability analysis provide the same results, and to determine how different factors such as the presence of water, tension cracks, and seismic forces affect the stability of these rock slopes. Firstly, field investigations were performed to obtain the engineering characteristics of the rock masses, discontinuities, and intact rocks of the slopes. Secondly, laboratory tests were carried out on rock samples obtained from the slopes, to determine the engineering properties of the intact rocks. Then for each rock slope, the contour diagram of discontinuities and slope face was drawn in the Dips v.5.1 software environment, and the failure mechanism was determined based on the kinematic or stereographic method. Next, the factors of safety of the rock slopes were calculated using the limit equilibrium method, based on the failure mechanisms resulting from the kinematic method. The accuracy of the results obtained by these two methods was investigated using SWedge v.4.0 software. The results indicated that four rock slopes have a potential for plane, wedge, and toppling failure, and three others are stable. Also, it was found that the stability of the studied rock slopes decreases greatly in the presence of water, tension cracks, and seismic forces.

Some Remarks on the Use of Deterministic and Probabilistic Approaches in the Evaluation of Rock Slope Stability

The rock slope stability assessment can be performed by means of deterministic and probabilistic approaches. As the deterministic analysis needs only representative values (generally, the mean value) for each physical and geo-mechanical parameter involved, it does not take into account the variability and uncertainty of geo-structural and geo-mechanical properties of joints. This analysis can be usually carried out using different methods, such as the Limit Equilibrium method or numerical modeling techniques sometimes implemented in graphical tests to identify different failure mechanisms (kinematic approach). Probabilistic methods (kinetic approach) aimed to calculate the slope failure probability, consider all orientations, physical characters and shear strength of joints and not only those recognized as kinematically possible. Consequently, the failure probability can be overestimated. It is, therefore, considered more realistic to perform both kinematic and kinetic analyses and to calculate a conditional probability given by the product of the kinematic and kinetic probabilities assuming that they are statistically independent variables. These approaches have been tested on two rock slopes in the Campanian region of Southern Italy affected by possible plane and wedge failures, respectively. Kinematic and kinetic probabilities have been evaluated both by means of the Markland’s test and the Monte Carlo simulation. Using the Eurocode 7, also a deterministic limit equilibrium analysis was performed. The obtained results were compared and commented on.

Evaluation of rock slopes susceptible to circular failures using logistic and multiple regression models

The analysis of stability of slopes is a classical problem for geotechnical engineers. In practice, many methods are available for the desired purpose, from basic kinematic analysis to two- and three-dimensional limit equilibrium analyses and numerical modeling with various user-friendly softwares. However, additional techniques are also required to provide knowledge necessary for decision-making. In this research, a reliable dataset provided by Sah et al. (1994) was used to analyze the stability evaluation of rock slopes subjected to circular failures. For this purpose, using Slide 2018 program, 44 separate limit equilibrium slope models were built for each case given in the original work. The provided material properties and slope geometries in heavily fractured and/or very weak or highly weathered rock masses were considered during the model building stage. It was found that Slide 2018 program generated dissimilar safety factors compared to those given by Sah et al. (1994) for the investigated slope cases. Binary logistic and multiple linear regression techniques were implemented in the study to promote alternative approaches for the prediction of the stability condition and safety factor (SF) of slopes excavated in heavily fractured/highly weathered rock masses. The condition of slopes (stable or failed) was predicted by binary logistic regression model with 90.9% accuracy. The SF of the slopes was estimated by a multiple linear regression model with 95.6% accuracy. It was concluded that both statistical techniques could be sufficiently used as alternative approaches to predict the stability condition and SF of rock slopes prone to circular (rotational) failures.

Evaluation of Rock Slope Stability based on Multi-Dimension Cloud Model

In this paper, slope stability is classified into five grades in terms of very steady, steady, basically steady, unsteady, and very unsteady. Ten indicators of slope height, tendency difference between structural plane and slope, structural plane inclination, etc., were selected. To solve the uncertainty and randomness, multi-dimension cloud model was applied with weights determined by projection pursuit method. The grade of steadiness was determined by maximum subject degree. The method was applied to 34 rock slopes to assess stability. The accuracy of the method reaches 50%, which indicates that the method has higher accuracy, and can be applied to other fields.

Prediction of the Shear Failure of Opened Rock Fractures and Implications for Rock Slope Stability Evaluation

Rock slope commonly fails due to the shear failure of rock fractures. Shear strength of rock fractures are reduced substantially once the fracture surfaces are mismatched or opened. We propose a new criterion to predict the shear strength of rock fractures in different opening states. The degree of interlocking representing the true asperity contact area is incorporated into the modified model of Saeb and Amadei. The effect of fracture opening on asperity dilation and degradation is separately considered. The transitional stress that is a critical parameter involved in the model is analytically determined based on energy consideration. The new model is validated with experimental results from direct shear tests on synthetic fractures with regular‐shaped asperities. Good agreement between the analytical solution and the experimental data confirms the capacity of the proposed model. Therefore, the model has great potential for assessing the stability of rock slopes where fractures are often opened due to stress relief and engineering disturbances.

Framework for susceptibility analysis of layered rock slopes considering the dimensions of the mapping units and geological data resolution at various map scales

In Taiwan, the failure of rock slopes has caused the catastrophic loss of lives and property. To understand the risks associated with rock slope failure, susceptibility analysis has been widely adopted as a fundamental task. However, currently, most susceptibility analyses have investigated only landslide occurrences and have been limited to the regional scale. In this case, susceptibility maps cannot provide detailed information about the rock slope stability as required by the engineers. To fill this gap, this study developed a methodological framework to analyze the susceptibility of layered rock slopes from regional to local scales. In each map scale, the appropriate size of the slope unit (SU) was produced as the mapping unit through the object-based image analysis (OBIA) method, and the susceptibility map was generated with an explicit purpose according to the resolution of geological data. Multiscale susceptibility analysis of layered rock slopes was performed in a metamorphic area in northern Taiwan. The performance of the susceptibility maps was validated by the field investigations and the data of the geologically sensitive area, which were released by the Central Geological Survey of Taiwan. The results show that different phases of the evaluation of rock slope stability were addressed, including the landslide activity and the rock slope characterization on the regional scale and the failure mechanisms on the local scale. In addition, suitable SUs can also be semiautomatically reproduced by the OBIA method with suggested strategies.

Numerical investigations on stability evaluation of a jointed rock slope during excavation using an optimized DDARF method

A jointed rock slope stability evaluation was simulated by a discontinuous deformation analysis numerical method to investigate the process and safety factors for different crack distributions and different overloading situations. An optimized method using Discontinuous Deformation Analysis for Rock Failure (DDARF) is presented to perform numerical investigations on the jointed rock slope stability evaluation of the Dagangshan hydropower station. During the pre-processing of establishing the numerical model, an integrated software system including AutoCAD, Screen Capture, and Excel is adopted to facilitate the implementation of the numerical model with random joint network. These optimizations during the pre-processing stage of DDARF can remarkably improve the simulation efficiency, making it possible for complex model calculation. In the numerical investigations on the jointed rock slope stability evaluations using the optimized DDARF, three calculation schemes have been taken into account in the numerical model: (I) no joint; (II) two sets of regular parallel joints; and (III) multiple sets of random joints. This model is capable of replicating the entire processes including crack initiation, propagation, formation of shear zones, and local failures, and thus is able to provide constructive suggestions to supporting schemes for the slope. Meanwhile, the overloading numerical simulations under the same three schemes have also been performed. Overloading safety factors of the three schemes are 5.68, 2.42 and 1.39, respectively, which are obtained by analyzing the displacement evolutions of key monitoring points during overloading.

A modified Hoek-Brown failure criterion considering the damage to reservoir bank slope rocks under water saturation-dehydration circulation

After water is impounded in a reservoir, rock mass in the hydro-fluctuation belt of the reservoir bank slope is subject to water saturationdehydration circulation (WSDC). To quantify the rate of change of rock mechanical properties, samples from the Longtan dam area were measured with uniaxial compression tests after different numbers (1, 5, 10, 15, and 20) of simulated WSDC cycles. Based on the curves derived from these tests, a modified Hoek- Brown failure criterion was proposed, in which a new parameter was introduced to model the cumulative damage to rocks after WSDC. A case of an engineering application was analyzed, and the results showed that the modified Hoek-Brown failure criterion is useful. Under similar WSDC-influenced engineering and geological conditions, rock mass strength parameters required for analysis and evaluation of rock slope stability can be estimated according to this modified Hoek-Brown failure criterion.

Parametric studies of disturbed rock slope stability based on finite element limit analysis methods

This study employs the finite element upper bound and lower bound limit analysis methods to investigate the stability of inhomogeneous rock slopes. The differences in the stability numbers of the upper and lower bound solutions are bracketed within ±10.5% or better, and the stability numbers obtained are presented in rock slope stability charts. These stability charts can provide a convenient tool for preliminary stability designs of inhomogeneous rock slopes. Various recommended blasting damage zones are considered, and disturbance factors are used to represent damage levels. Results showed that rock mass disturbance could significantly influence the evaluation of rock slope stability.

Systematic Approach to Sustainable Rock Slope Stability Evaluation

Geological discontinuities play an important role in the evaluation of rock slope stability. Romana's Slope Mass Rating (SMR) system provides a methodology to quantify rock slope stability. Employing Bieniawski's Rock Mass Rating (RMR) to classify the rock mass of an investigated slope, SMR enables an objective determination of the rating adjustment values based on discontinuity orientation-slope orientation, respective dips angles and slope excavation methods. However the surface roughness of the discontinuities and their peak friction angles (αp) that are fundamental in determining rock slope stability are not directly considered in this evaluation. A more sustainable approach to rock slope stability assessment proposed here combines the SMR determination with the determination of the peak friction angle, αp of the discontinuity surfaces. Based on this proposal, the potential for slope failure can be quantified as follows: if SMR predicts failure and dip angle of the discontinuity (βi) > the peak friction angle (αp) the slope has a very high failure potential; if SMR predicts failure and βi < αp, the slope has intermediate failure potential; if the slope is stable according to SMR & βi > αp, the slope has low failure potential and if stable according to SMR and βi < αp, the slope can be considered as stable.

Evaluation of rock slope stability for a touristic coastal area near Kusadasi, Aydin (Turkey)

The study area, which will be open to tourism in Kusadasi (Aydin), has steep and high cliffs on the Aegean coast in Turkey. Flysch is the main lithological unit and consists of alternating sandstone–claystone–marl sequences. Some sliding and rockfall problems have occurred in the area in the past, so potential geological hazards need to be investigated to ensure the safety of tourists. The aim of this study is to mitigate geological hazards by recommending engineering solutions, which will ensure the continuation of the nature-friendly appearance of the slopes. To accomplish these tasks, a geological survey was performed. It involved gathering information on rock discontinuities by means of scan-line surveys and collection of rock samples. Furthermore, in situ and laboratory tests were also carried out. The data collected from the field and laboratory test results were used to perform slope stability and rockfall (2-D and 3-D) analyses for different slope conditions along 43 profiles. Based on the analyses, rockfall was found to be the main slope instability problem in the study area. Under the light of these studies, rock removal, drainage, greening (vegetation), filling of caverns, protective wall building and erosion prevention are offered as remedial measures.

Rock Slope Stability Evaluation in a Steep-Walled Canyon: Application to Elevator Construction in the Yunlong River Valley, Enshi, China

A passenger elevator is to be built on a nearly vertical slope in the National Geological Park in Enshi, Hubei province, China. Three steps comprise the construction: excavating the slope toe for the elevator platform, building the elevator on the platform, and affixing the elevator to the slope using anchors. To evaluate the rock slope stability in the elevator area and the safety of the elevator construction, we applied three techniques: qualitative analysis, formula calculation, and numerical simulation methods, based on field investigation and parameter selection, and considering both wet and dry conditions, pre- and post-construction. Qualitative stability factors for sliding and falling were calculated using the limit equilibrium method; the results show that the slope as a whole is stable, with a few unstable blocks, notably block BT1. Formula-based stability factors were calculated for four sections on block BT1, revealing the following: anchors will decrease the stability of certain rock pieces; the lowest average stability factor after anchoring will be K f = 1.36 in wet conditions; block BT1 should be reinforced during elevator construction, up to a first-class slope stability factor of K f = 1.40; and the slope as a whole is stable. Numerical simulation using FLAC3D indicated that the stress distribution will reach equilibrium for all steps before and after construction, and that the factor of safety (FOS) is within the general slope safety range (FOS > 1.05). We suggest that unstable pieces in block BT1 be reinforced during construction to a first-class slope safety range (FOS > 1.3), and that deformation monitoring on the slope surface be implemented.

Stability evaluation model for high rock slope based on element extension theory

The multi-level evaluation system and rock slope stability were analyzed in this study based on extension and systems engineering theory. An appropriate evaluation index system was selected through hierarchical analysis of geological conditions, excavation and supporting measures, and environmental and monitoring layouts. The comprehensive evaluation system was then divided into three layers: index, description, and target layers. The system can be adopted to conduct a thorough and careful investigation of the research object. The technique matter-element extension transform was employed in the extension model to solve the multi-attribute problem and to prevent incompatibility in rock slope stability evaluation. Qualitative and quantitative grade evaluations were performed by calculating the matter-element dependency degree. The model was then applied to a large-scale rock slope project, and its evaluation criteria for rock slope stability were established. Results were verified through quantitative method of 3D limit equilibrium and qualitative method of 3D nephrogram displacement variation. Results show that extension theory can be utilized to solve problems in rock slope safety.