General limit equilibrium method for lateral earth force

1984 ◽  
Vol 21 (1) ◽  
pp. 166-175 ◽  
Author(s):  
Harianto Rahardjo ◽  
Delwyn G. Fredlund
Keyword(s):  
Shear Strength ◽  
Slip Surface ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Vertical Wall ◽  
Limit Equilibrium Method ◽  
External Loading ◽  
Equilibrium Method ◽  
General Limit

The calculation of the lateral earth force using the limit equilibrium method of slices is an indeterminate problem. An assumption regarding the direction or the magnitude of certain forces, or the position of the line of thrust can be used to render the problem determinate.A general formulation for the lateral earth force is derived in accordance with the assumptions involved in the general limit equilibrium (GLE) method. An assumption concerning a direction of the interslice forces is utilized to solve the problem of indeterminancy. Horizontal force equilibrium conditions within a sliding mass are used to compute the magnitude of the active and passive forces. The point of application of the lateral earth force is obtained by considering moment equilibrium for each slice.The coefficient of lateral earth force obtained from the GLE method agrees closely with the results obtained from most other theories. Comparisons are made to the Coulomb theory (i.e., using a planar slip surface) and other theories using a curved or a composite slip surface.Data are presented for the case of a horizontal cohesionless backfill against a vertical wall. The lateral earth force can be contoured on the grid of centers of rotation. These contours have a bell-shaped characteristic and can be used to locate the critical center of rotation.The main advantage of this method lies in its capability to analyze arbitrarily stratified soil deposits with complex geometries. Different conditions of pore-water pressure, shear strength, and external loading can be accommodated in the analysis. Factors of safety greater than 1.0 can be applied to the shear strength of the soil for design purposes. Keywords: lateral earth force, active force, passive force, general limit equilibrium, interslice forces, and coefficient of lateral earth force.

Research on 2D Limit Equilibrium Method of Slopes Considering the Effect of Horizontal In Situ Stress

2013 ◽  
Vol 671-674 ◽  
pp. 245-250
Author(s):  
Wen Hui Tan ◽  
Ya Liang Li ◽  
Cong Cong Li
Keyword(s):  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
In Situ Stress ◽  
Open Pit ◽  
Open Pit Mines ◽  
Equilibrium Method ◽  
Iron Mine ◽  
The Stability ◽  
Slice Method

At present, in-situ stress was not considered in Limit Equilibrium Method (LEM) of slopes, the influence of in-situ stress is very small on the stability of conventional slopes, but in deep-depressed open-pit mines, the influence should not be neglected. Formula for calculating the Factor of Safety (FOS) under the effect of horizontal in-situ stress was deduced using General Slice Method (GSM) of two-dimensional (2D) limit equilibrium method in this paper，a corresponding program SSLOPE was built, and the software was used in a deep- depressed open-pit iron mine. The results show that the FOS of the slope decreased by 20% when horizontal in-situ stress is considered, some reinforcements must be taken. Therefore, the influence of in-situ stress on slope stability should be taken into account in deep open –pit mines.

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.

Some difficulties associated with the limit equilibrium method of slices

1983 ◽  
Vol 20 (4) ◽  
pp. 661-672 ◽  
Author(s):  
R. K. H. Ching ◽  
D. G. Fredlund
Keyword(s):  
Slope Stability ◽  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Stability Limit ◽  
Limit Equilibrium Method ◽  
Soil Conditions ◽  
Side Force ◽  
Limit Equilibrium Methods ◽  
Equilibrium Method ◽  
The Stability

Several commonly encountered problems associated with the limit equilibrium methods of slices are discussed. These problems are primarily related to the assumptions used to render the inherently indeterminate analysis determinate. When these problems occur in the stability computations, unreasonable solutions are often obtained. It appears that problems occur mainly in situations where the assumption to render the analysis determinate seriously departs from realistic soil conditions. These problems should not, in general, discourage the use of the method of slices. Example problems are presented to illustrate these difficulties and suggestions are proposed to resolve these problems. Keywords: slope stability, limit equilibrium, method of slices, factor of safety, side force function.

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