scholarly journals Numerical Computation of Homogeneous Slope Stability

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Shuangshuang Xiao ◽  
Kemin Li ◽  
Xiaohua Ding ◽  
Tong Liu
Keyword(s):  
Slope Stability ◽  
High Efficiency ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Computation Time ◽  
Computational Accuracy ◽  
Slope Analysis ◽  
Slip Surfaces ◽  
Simple Slope ◽  
Computation Error

To simplify the computational process of homogeneous slope stability, improve computational accuracy, and find multiple potential slip surfaces of a complex geometric slope, this study utilized the limit equilibrium method to derive expression equations of overall and partial factors of safety. This study transformed the solution of the minimum factor of safety (FOS) to solving of a constrained nonlinear programming problem and applied an exhaustive method (EM) and particle swarm optimization algorithm (PSO) to this problem. In simple slope examples, the computational results using an EM and PSO were close to those obtained using other methods. Compared to the EM, the PSO had a small computation error and a significantly shorter computation time. As a result, the PSO could precisely calculate the slope FOS with high efficiency. The example of the multistage slope analysis indicated that this slope had two potential slip surfaces. The factors of safety were 1.1182 and 1.1560, respectively. The differences between these and the minimum FOS (1.0759) were small, but the positions of the slip surfaces were completely different than the critical slip surface (CSS).

A method for locating critical slip surfaces in slope stability analysis

2001 ◽  
Vol 38 (2) ◽  
pp. 328-337 ◽  
Author(s):  
Da-Yong Zhu
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Factor Of Safety ◽  
High Efficiency ◽  
Slip Surface ◽  
Numerical Procedure ◽  
Slope Stability Analysis ◽  
Case Examples ◽  
Slip Surfaces ◽  
Global And Local

This paper presents a new method for locating critical slip surfaces of general shapes in slope stability analysis. On the basis of the principle of optimality, along with the method of slices, a critical slip field (CSF) in a slope is postulated which consists of a family of slip surfaces having maximum values of unbalanced thrust forces at exit points on the slope face. A numerical procedure is developed for constructing the CSF. The critical slip surface having minimum factor of safety is included in the CSF. All the critical slip surfaces corresponding to all of the exit points are thus determined consecutively, resulting in a global critical slip field (GCSF) which exhibits both global and local slope stability. Comparisons with other methods are made which indicate the high efficiency and accuracy of the proposed approach. Applications of the proposed method to two case examples are given, the results of which demonstrate its applicability to practical engineering.Key words: slope, stability, analysis, factor of safety, critical slip field.

Effect of the axis of moment equilibrium in slope stability analysis

1992 ◽  
Vol 29 (3) ◽  
pp. 456-465 ◽  
Author(s):  
D. G. Fredlund ◽  
Z. M. Zhang ◽  
L. Lam
Keyword(s):  
Slope Stability ◽  
Factor Of Safety ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Stability Limit ◽  
Slip Surfaces ◽  
Moment Equilibrium ◽  
Simplified Method ◽  
General Limit ◽  
The Moment

Some of the methods of slices satisfying moment equilibrium derived for circular slip surfaces have been extended to accommodate noncircular (or composite) type slip surfaces. A question arises regarding the point about which moment equilibrium should be taken and whether varying the center for moment equilibrium has a significant effect upon the computed factor of safety. This paper addresses the question of the effect of the center for moment equilibrium as it pertains to noncircular (or composite) slip surfaces. In particular, extensions of the Ordinary, Bishop's simplified, and the General Limit Equilibrium (GLE) methods are examined. The results show that considerable variations in the factor of safety can occur when using the extended Ordinary method. The extended Bishop's simplified method shows varying factors of safety as the moment axis moves vertically. Variations in the computed factor of safety can generally be expected to be less than 12%. The GLE, Morgerstern–Price, and Spencer methods are independent of the axis for moment equilibrium. Key words : slope stability, limit equilibrium, moment equilibrium, factor of safety, noncircular slip surface.

Slope Stability Analysis of Elastic Limit Equilibrium Method

2013 ◽  
Vol 275-277 ◽  
pp. 1423-1426
Author(s):  
Lin Kuang ◽  
Ai Zhong Lv ◽  
Yu Zhou
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Safety Factor ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Slope Stability Analysis ◽  
Sliding Surface ◽  
Tangential Stresses ◽  
Equilibrium Method

Based on finite element analysis software ANSYS, slope stability analysis is carried out by Elastic limiting equilibrium method proposed in this paper. A series of sliding surface of the slope can be assumed firstly, and then stress field along the sliding surface is analyzed as the slope is in elastic state. The normal and tangential stresses along each sliding surface can be obtained, respectively. Then the safety factor for each slip surface can be calculated, the slip surface which the safety factor is smallest is the most dangerous sliding surface. This method is different from the previous limit equilibrium method. For the previous limit equilibrium method, the normal and tangential stresses along the sliding surface are calculated based on many assumptions. While, the limit equilibrium method proposed in this paper has fewer assumptions and clear physical meaning.

Convergence aspect of limit equilibrium methods for slopes

1990 ◽  
Vol 27 (1) ◽  
pp. 145-151 ◽  
Author(s):  
R. N. Chowdhury ◽  
S. Zhang
Keyword(s):  
Factor Of Safety ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Solution Process ◽  
Iterative Solution ◽  
Friction Angle ◽  
Equilibrium Analysis ◽  
Negative Slope ◽  
Slip Surfaces ◽  
Geological Discontinuity

This note is concerned with the multiplicity of solutions for the factor of safety that may be obtained on the basis of the method of slices. Discontinuities in the function for the factor of safety are discussed and the reasons for false convergence in any iterative solution process are explored, with particular reference to the well-known Bishop simplified method (circular slip surfaces) and Janbu simplified or generalized method (slip surfaces of arbitrary shape). The note emphasizes that both the solution method and the method of searching for the critical slip surface must be considered in assessing the potential for numerical difficulties and false convergence. Direct search methods for optimization (e.g., the simplex reflection method) appear to be superior to the grid search or repeated trial methods in this respect. To avoid false convergence, the initially assumed value of factor of safety F0 should be greater than β1(=−tan α1 tan [Formula: see text]) where α1 and [Formula: see text] are respectively the base inclination and internal friction angle of the first slice near the toe of a slope, the slice with the largest negative reverse inclination. A value of F0 = 1 + β1, is recommended on the basis of experience. If there is no slice with a negative slope for any of the slip surfaces generated in the automatic, search process, then any positive value of F0 will lead to true convergence for F. It is necessary to emphasize that no slip surface needs to be rejected for computational reasons except for Sarma's methods and similarly no artificial changes need to be made to the value of [Formula: see text] except for Sarma's methods. Key words: slope stability, convergence, limit equilibrium, analysis, optimization, slip surfaces, geological discontinuity, simplex reflection technique.

scholarly journals Slope Stability Analysis Based on Measured Strains along Soil Nails Using FBG Sensing Technology

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Hua-Fu Pei ◽  
Chao Li ◽  
Hong-Hu Zhu ◽  
Yu-Jie Wang
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Cross Section ◽  
Slip Surface ◽  
Axial Stress ◽  
Limit Equilibrium ◽  
Cost Effective ◽  
Slope Stability Analysis ◽  
Actual Condition ◽  
Soil Nails

In the past few decades, slope stability analysis using numerical methods is becoming a hot issue, but it is based on extremely ideal assumptions. Soil nailing technique, as one of the most cost-effective reinforcing methods, has already been widely used for reinforcing slopes. In this study, to evaluate the safety factor of a slope, the strains on soil nails were measured by fiber Bragg grating (FBG) sensor. Strains along soil nails in the same cross section of a slope can be computed using the measured wavelength shifts of FBG sensors. In order to evaluate the stability of a slope, an optimal model was proposed to search the potential slip surfaces based on measured strain values. Maximum sum of strains on soil nails at different elevations of the same cross section was taken as the objective. Positions of soil nails, circular slip surface, and boundary conditions of the soil nails were summarized and taken as constraints. Finally, safety factors can be computed using the searched slip surface regarding the axial stress of soil nails. This method combines the limit equilibrium methods with measured axial strains on site which can reflect the actual condition of field slopes.

Improved general slice method of limit equilibrium for slope stability analysis

2021 ◽  
Vol 18 (1) ◽  
pp. 55-64
Author(s):  
Shiguo Xiao ◽  
Tingjun Chen
Keyword(s):  
Linear Programming ◽  
Stability Analysis ◽  
Energy Dissipation ◽  
Slope Stability ◽  
Limit Equilibrium ◽  
Slope Stability Analysis ◽  
Equilibrium Conditions ◽  
Non Linear Programming ◽  
Slip Surfaces ◽  
Slice Method

For traditional slice methods of limit equilibrium used to analyze slope stability, some hypothetical conditions on interslice force are generally introduced to solve the problem. In order to reduce the defect theoretically due to the related hypothesis, more rigorous constraints of interslice force are completely considered in light of static equilibrium conditions and energy dissipation principle of the interface between two adjacent slices. Without hypothesis of interslice force, the slope stability analysis is transformed consistently into a non-linear programming problem to be solved. So, a generally improved solution of slice method of limit equilibrium to slope stability is put forward. In particular, influence of the dilation angle of soil on slope stability can be involved in the method. The proposed method can be utilized for any slopes with arbitrary slip surfaces.

Determination of three-dimensional shape of failure in soil slopes

2015 ◽  
Vol 52 (9) ◽  
pp. 1283-1301 ◽  
Author(s):  
Roohollah Kalatehjari ◽  
Ali Arefnia ◽  
Ahmad Safuan A Rashid ◽  
Nazri Ali ◽  
Mohsen Hajihassani
Keyword(s):  
Slope Stability ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Three Dimensional ◽  
Failure Surface ◽  
Small Scale ◽  
3D Shape ◽  
Finite Element Software ◽  
Soil Slopes ◽  
3D Slope Stability

This paper presents the application of particle swarm optimization (PSO) in three-dimensional (3D) slope stability analysis to determine the shape and direction of failure as the critical slip surface. A detailed description of adopted PSO is presented and a rotating ellipsoidal shape is introduced as the possible failure surface in the analysis. Based on the limit equilibrium method, an equation of factor of safety (FoS) was developed with the ability to calculate the direction of sliding (DoS) in its internal process. A computer code was developed in Matlab to determine the 3D shape of the failure surface and calculate its FoS and DoS. Then, two example problems were used to verify the applicability of the presented code, the first by conducting a comparison between the results of the code and PLAXIS-3D finite element software and the second by re-analyzing an example from the literature to find the 3D failure surface. In addition, a hypothetical 3D asymmetric slope was introduced and analyzed to demonstrate the ability of the presented method to determine the shape and DOS of failure in 3D slope stability problems. Finally, a small-scale physical model of a 3D slope under vertical load was constructed and tested in the laboratory and the results were re-analyzed and compared with the code results. The results demonstrate the efficiency and effectiveness of the presented code in determining the 3D shape of the failure surface in soil slopes.

A Comparative Study on Locating Critical Slip Surface in 2D and 3D Limit Equilibrium Stability Analysis of Slopes

2012 ◽  
Vol 446-449 ◽  
pp. 1905-1913
Author(s):  
Mo Wen Xie ◽  
Zeng Fu Wang ◽  
Xiang Yu Liu ◽  
Ning Jia
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Safety Factor ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Three Dimensional ◽  
Slope Stability Analysis ◽  
Equilibrium Stability ◽  
Critical Slip Surface ◽  
Minimum Safety Factor

The Various methods of optimization or random search have been developed for locating the critical slip surface of a slope and the related minimum safety factor in the limit equilibrium stability analysis of slope. But all these methods are based on a two-dimensional (2D) method and no one had been adapted for a search of the three-dimensional (3D) critical slip surface. In this paper, a new Monte Carlo random simulating method has been proposed to identify the 3D critical slip surface, in which assuming the initial slip to be the lower part of an ellipsoid, the 3D critical slip surface in the 3D slope stability analysis is located by minimizing the 3D safety factor of limit equilibrium approach. Based on the column-based three-dimensional limit equilibrium slope stability analysis models, new Geographic Information Systems (GIS) grid-based 3D deterministic limit equilibrium models are developed to calculate the 3D safety factors. Several practical examples, of obtained minimum safety factor and its critical slip surface by a 2D optimization or random technique, are extended to 3D slope problems to locate the 3D critical slip surface and to compare with the 2D results. The results shows that, comparing with the 2D results, the resulting 3D critical slip surface has no apparent difference only from a cross section, but the associated 3D safety factor is definitely higher.

Search of the Most Dangerous in Slide Slope Stability Analysis Based on Genetic Algorithm

2012 ◽  
Vol 166-169 ◽  
pp. 2535-2538
Author(s):  
Ke Wang ◽  
Chang Ming Wang ◽  
Fang Qi ◽  
Cen Cen Niu
Keyword(s):  
Genetic Algorithm ◽  
Stability Analysis ◽  
Slope Stability ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Evolutionary Process ◽  
Limit Equilibrium Method ◽  
Slope Stability Analysis ◽  
Equilibrium Method ◽  
The Stability

The traditional limit equilibrium method in the analysis of slope stability not only exists some subjective empirical hypothesis that can not meet the equilibrium of force and moment, but also ignores the effects of internal stress and strain on the slope stability. Furthermore, in the stability of the slope evaluation, limit equilibrium method relies too much on experience when hypothesizing the slope slip surface. So that it makes deviation on slope analysis and stability evaluation. This paper is based on simplified Bishop method used to establish the model of slope stability analysis. And it used genetic algorithms to solve the minimum safety factor and the most dangerous slip surface of slope. It was the arithmetic which simulates organisms genetic evolutionary process and it avoided the traditional methods falling into the local extreme value point easily and error propagation leading to convergence. The algorithm had advantages of higher accuracy, quick convergence and applicability. It showed that the genetic algorithm is accurate and reliable in the analysis of slope stability.

scholarly journals Extension of Spencer’s Circular Model to Stability Analysis of Landslides with Multicircular Slip Surfaces

2020 ◽  
Vol 2020 ◽  
pp. 1-22
Author(s):  
Zhiqiang Fan ◽  
Huiming Tang ◽  
Yingming Yang ◽  
Yanhao Zheng ◽  
Qinwen Tan ◽  
...  
Keyword(s):  
Slip Surface ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Slip Surfaces ◽  
Circular Model ◽  
The Three Gorges ◽  
Local Slip ◽  
Centre Of Rotation

This paper presents a new limit equilibrium method based on analysis of landslides with multicircular slip surfaces in the Three Gorges Reservoir area, China. An important innovation of this method is that the rigid sliding mass is divided into numerous interrelated Spencer’s circles sharing the same factor of stability, so that each of them possesses a real centre of rotation and an independent inclination of interslice forces. The analysis is accomplished by iterations to satisfy both force and moment equilibrium for each circle. Two real cases were then adopted to verify the effectiveness of the method in the analysis of both slope stability and the design forces on piles. Factors influencing the performance of the method were also investigated, which reveal that the concavity of the local slip surface near the slope toe has a major impact. The importance of the proximity between the actual and the fitted sliding surfaces was highlighted for ensuring accuracy of the method when extended to the real cases.

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