scholarly journals Comparative study of material point method and upper bound limit analysis in slope stability analysis

2020 ◽  
Vol 2 (1) ◽  
pp. 44-57
Author(s):  
Lianheng Zhao ◽  
Nan Qiao ◽  
Zhigang Zhao ◽  
Shi Zuo ◽  
Xiang Wang

Abstract The upper bound limit analysis (UBLA) is one of the key research directions in geotechnical engineering and is widely used in engineering practice. UBLA assumes that the slip surface with the minimum factor of safety (FSmin) is the critical slip surface, and then applies it to slope stability analysis. However, the hypothesis of UBLA has not been systematically verified, which may be due to the fact that the traditional numerical method is difficult to simulate the large deformation. In this study, in order to systematically verify the assumption of UBLA, material point method (MPM), which is suitable to simulate the large deformation of continuous media, is used to simulate the whole process of the slope failure, including the large-scale transportation and deposition of soil mass after slope failure. And a series of comparative studies are conducted on the stability of cohesive slopes using UBLA and MPM. The proposed study indicated that the slope angle, internal friction angle and cohesion have a remarkable effect on the slip surface of the cohesive slope. Also, for stable slopes, the calculation results of the two are relatively close. However, for unstable slopes, the slider volume determined by the UBLA is much smaller than the slider volume determined by the MPM. In other words, for unstable slopes, the critical slip surface of UBLA is very different from the slip surface when the slope failure occurs, and when the UBLA is applied to the stability analysis of unstable slope, it will lead to extremely unfavorable results.

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Zhen Wang ◽  
Xumeng Yang ◽  
Ang Li

Slope stability analysis is a core issue in geotechnical engineering. This paper proposes a method of upper bound limit stability analysis for a slope with multiparameter coordinated variation based on the comprehensive consideration of the nonuniform distribution of slope soil parameters. This method starts from the perspective of energy balance, establishes a slope failure mechanism which meets velocity separation requirements, deduces its calculation formula for external force power and internal energy dissipation power, develops a cycle program for the most dangerous slip surface searching and stability coefficient calculation through computer programming technology, and finally forms a calculation method of upper bound limit stability analysis for the soil slope with nonuniform multiparameter distribution. At the same time, this method takes a dump slope in an open-pit mine as the engineering background, considers the nonuniformity of density, cohesion, and internal friction angle of the slope soil under subsidence, applies upper bound limit analysis to analyze the slope stability, and evaluates the accuracy of analysis results by using the residual thrust method. The results show that upper bound limit analysis has highly accuracy in stability coefficient calculation; compared with the residual thrust method, the stability coefficient calculation result by upper bound limit analysis is a strict upper bound solution, and the calculation error is easy to be estimated and eliminated. Simultaneously, the most dangerous slip surface obtained by upper bound limit analysis can fully satisfy the velocity separation requirement and has a greater engineering reference value.


2021 ◽  
Vol 112 ◽  
pp. 103904
Author(s):  
Fabricio Fernández ◽  
Jhonatan E.G. Rojas ◽  
Eurípedes A. Vargas ◽  
Raquel Q. Velloso ◽  
Daniel Dias

2013 ◽  
Vol 353-356 ◽  
pp. 895-900 ◽  
Author(s):  
Xin Rong Liu ◽  
Ming Xi Ou ◽  
Xin Yang

In view of the shortage of using classical earth pressure theories to calculating passive earth pressure of cohesive soil on retaining wall under complex conditions. Based on the planar slip surface and the back of retaining wall was inclined and rough assumption, the calculation model of passive earth pressure of cohesive backfill under uniformly distrubuted loads was presented, in which the upper bound limit analysis was adopted. Meanwhile it was proven that the prevailing classical Rankine’s earth pressure theory was a special example simlified under the condition of its assumptions. For it’s difficult to determine the angle of slip surface , a relatively simple method for calculating the angle was proposed by example. And the influence of angle of wall back , friction angle of the interface between soil and retaining wall, cohesion force and internal friction angle of backfill soil to planar sliding surface and passive earth pressure were analyzed. Some good calculation results were achieved, these analysis can provide useful reference for the design of retaining wall.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Yu-chuan Yang ◽  
Hui-ge Xing ◽  
Xing-guo Yang ◽  
Jia-wen Zhou

The slope stability problem is an important issue for the safety of human beings and structures. The stability analysis of the three-dimensional (3D) slope is essential to prevent landslides, but the most important and difficult problem is how to determine the 3D critical slip surface with the minimum factor of safety in earth slopes. Basing on the slope stress field with the finite element method, a stability analysis method is proposed to determine the critical slip surface and the corresponding safety factor of 3D soil slopes. Spherical and ellipsoidal slip surfaces are considered through the analysis. The moment equilibrium is used to compute the safety factor combined with the Mohr-Coulomb criteria and the limit equilibrium principle. Some assumptions are introduced to reduce the search range of center points and the radius of spheres or ellipsoids. The proposed method is validated by a classical 3D benchmark soil slope. Simulated results indicate that the safety factor of the benchmark slope is 2.14 using the spherical slip surface and 2.19 using the ellipsoidal slip surface, which is close to the results of previous methods. The simulated results indicate that the proposed method can be used for the stability analysis of a 3D soil slope.


2022 ◽  
Vol 148 (3) ◽  
Author(s):  
J. Y. Zuo ◽  
B. T. Wang ◽  
W. W. Li ◽  
H. X. Zhang

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