scholarly journals A limit equilibrium analysis of progressive failure in the stability of slopes

1978 ◽  
Vol 15 (1) ◽  
pp. 113-122 ◽  
Author(s):  
K. Tim Law ◽  
Peter Lumb
Keyword(s):  
Slip Surface ◽  
Progressive Failure ◽  
Limit Equilibrium ◽  
Friction Angle ◽  
Soil Mass ◽  
Local Failure ◽  
Equilibrium Analysis ◽  
Stability Of Slopes ◽  
The Stability ◽  
Definition Of

A limit equilibrium method of analysis is proposed for the study of progressive failure in slope stability under a long-term condition. Based on effective stresses, the formulation of the method is derived from consideration of force and moment equilibrium within the soil mass above a prospective slip surface. By dividing the soil mass into a number of vertical slices, recognition of local failure can be made. Once local failure takes place, post-peak strength is assumed to be operative. This then initiates a redistribution of interslice forces and leads to some further local failure. Thus realistic available strengths along the slip surface can be evaluated. This permits the definition of a final safety factor, which is expressed in terms of the actual available reserve of strength. The proposed method has been applied to three well documented case records and encouraging results have been obtained. Based on the assumption that post-peak strengths are given by a friction angle equal to the peak value and a zero cohesion, stability charts have been prepared for design purposes.

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.

Three-dimensional slope stability based on stresses from a stress-deformation analysis

2011 ◽  
Vol 48 (6) ◽  
pp. 891-904 ◽  
Author(s):  
J.R. Stianson ◽  
D.G. Fredlund ◽  
D. Chan
Keyword(s):  
Stress Distribution ◽  
Slope Stability ◽  
Internal Stress ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Three Dimensional ◽  
Equilibrium Analysis ◽  
Deformation Analysis ◽  
Stress Deformation ◽  
The Stability

A procedure is developed where stresses from a finite element analysis are incorporated into a limit equilibrium framework to evaluate the stability of three-dimensional slopes. An independent stress-deformation analysis is performed to calculate the internal stress state for the slope. The stress distribution is imported into the three-dimensional slope stability analysis in the form of a regular grid. The slip surfaces considered in the limit equilibrium analysis are ellipsoidal and discretized using a series of triangular planes. The normal and shear force acting at the centroid of individual triangular planes can be computed from the internal stress distribution. Subsequently, the factor of safety of a selected slip surface can be calculated directly without using an iterative procedure. A series of verification examples are presented to confirm that the proposed method provides the required accuracy and flexibility to assess the stability of slopes typically encountered in practice. Sensitivity analyses are presented to show how the procedure used to compute the forces acting on each triangular plane, the number of planes used to discretize the slip surface, and Poisson’s ratio influence the computed factors of safety, but do not limit the successful application of the methodology.

Stability of Slopes in Anisotropic, Nonhomogeneous Soils

1975 ◽  
Vol 12 (1) ◽  
pp. 146-152 ◽  
Author(s):  
W. F. Chen ◽  
N. Snitbhan ◽  
H. Y. Fang
Keyword(s):  
Upper Bound ◽  
Limit Analysis ◽  
Limit Equilibrium ◽  
Equilibrium Analysis ◽  
Stability Factor ◽  
Failure Plane ◽  
Limit Equilibrium Analysis ◽  
Stability Of Slopes ◽  
Upper Bound Technique ◽  
The Stability

The upper bound technique of limit analysis has been found to be very successful in analyzing the stability of cuttings in normally consolidated clays. However, most soils in their natural states exhibit some anisotropy with respect to shear strength, and some nonhomogeneity with respect to depth. It is difficult to obtain the solution based on the classical limit equilibrium analysis with the assumed noncircular failure plane with such soil properties included. This paper establishes an expression for the stability factor Ns, based on the upper bound technique of limit analysis which yields a close-formed solution for sections in which the following conditions are considered: (a) log-spiral failure-plane, through and below toe; (b) non-homogeneity; (c) anisotropy; and (d) general slope.

Searching of Critical Slip Surface of Slope Based on Bionics Algorithm

2010 ◽  
Vol 156-157 ◽  
pp. 1335-1338
Author(s):  
Wei Gao ◽  
Lu Yu Zhang
Keyword(s):  
Ant Colony Algorithm ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Continuous Optimization ◽  
Function Optimization ◽  
Ant Colony ◽  
Equilibrium Analysis ◽  
Critical Slip Surface ◽  
Artificial Immune System Algorithm ◽  
The Stability

The landslides from the instability of slopes are very serious geological hazards. The one key issue to compute the slope stability is the searching of critical slip surface. Generally, the searching of critical slip surface is a very typical complicated continuous optimization problem. To solve this problem very well, firstly, combing the artificial immune system algorithm and evolutionary algorithm with continuous ant colony algorithm, one new bionics algorithm for continuous function optimization which is called immunized continuous ant colony algorithm is proposed, secondly, combing new algorithm with limit equilibrium analysis, one new global optimization algorithm for critical slip surface searching is proposed. At last, through a typical numerical example-ACADS example, this new method is verified. The results show that, using the new algorithm, the searched slip surface will be coincided with the measured slip surface very well, and the stability safety factor will also be agree with the actual situation.

Limit equilibrium method with local factors of safety for slope stability

1987 ◽  
Vol 24 (4) ◽  
pp. 652-656 ◽  
Author(s):  
Milutin M. Srbulov
Keyword(s):  
Slope Stability ◽  
Limit Equilibrium ◽  
Soil Mass ◽  
Local Factors ◽  
A Value ◽  
Equilibrium Approach ◽  
Current Design ◽  
Soil Strain ◽  
The Stability ◽  
Definition Of

Current design practice often involves the consideration of slope stability when the strength parameters of the soil or the pore pressures vary considerably within a slope. In these cases it is evident that, because of departures from homogeneity, the soil mass may slip along a noncircular surface and local overstress will occur if the factor of safety lies below a value of about 1.8. Overstress also occurs when a slope contains materials that activate their shear resistances under significantly different stress – strain relationships. Therefore, the objective of this paper is to describe a new limit equilibrium approach suitable for the consideration of the heterogeneous slopes. A new definition of local factors of safety distribution, not only along a trial sliding surface but also at the interfaces of wedge-shaped slices, is introduced considering the soil strain properties. The main features of the comptutational procedure are outlined. One illustrative example dealing with the stability of a heterogeneous slope is included. Key words: limit equilibrium, slope stability, local factors of safety.

scholarly journals Sensitivity Analysis on Stability Parameters in Landfill

2015 ◽  
Vol 9 (1) ◽  
pp. 108-111 ◽  
Author(s):  
Sun Hong-Jun ◽  
Fan Yan-Chao ◽  
Zhao Li-Hong
Keyword(s):  
Safety Factor ◽  
Limit Equilibrium ◽  
Slope Angle ◽  
Friction Angle ◽  
Equilibrium Analysis ◽  
Stability Parameters ◽  
Limit Equilibrium Analysis ◽  
Sensitivity Curves ◽  
Overall Stability ◽  
The Stability

To study the stability of waste body failure in landfill, the landfill was divided into two parts: an active wedge and a passive wedge. A limit equilibrium analysis was used to calculate the safety factor of stability in landfill. The parameters which affected the stability of the landfill were discussed. Sensitivity curves of each parameter were proposed and effect trends of various parameters on safety factor were analyzed. Cohesion c and internal friction angle фs increases linearly with the safety factor. The safety factor decreases with increasing slope angle β and filled height H. The safety factor of after landfill settlement was higher than the safety factor of settlement which did not occur. It increases the overall stability about 16%.

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