Revisiting the three-dimensional slope stability problem in clay

2012 ◽  
Vol 49 (4) ◽  
pp. 494-498 ◽  
Author(s):  
Fei Cai ◽  
Atsushi Nakamura ◽  
Keizo Ugai
Keyword(s):  
Safety Factor ◽  
Stability Problem ◽  
Limit Equilibrium ◽  
Three Dimensional ◽  
Failure Surface ◽  
Benchmark Problem ◽  
Integral Expression ◽  
Equilibrium Conditions ◽  
Limit Equilibrium Methods ◽  
Force Equilibrium

This note revisits the benchmark problem involving a spherical failure surface in clay, gives an integral expression for the safety factor defined in terms of moments, and points out the mistakes in the solution of Silvestri. An integral expression for the safety factor of three-dimensional simplified Janbu’s method is also presented to facilitate the validation of three-dimensional limit equilibrium methods that satisfy force equilibrium conditions.

scholarly journals The Influence of Initial Normal Stress Assumption of Slip Surface on Safety Factor of Symmetrical Three-Dimensional Slopes

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Huali Liu
Keyword(s):  
Stress Distribution ◽  
Normal Stress ◽  
Safety Factor ◽  
Slip Surface ◽  
Three Dimensional ◽  
Normal Stresses ◽  
Equilibrium Conditions ◽  
Normal Stress Distribution ◽  
A Value ◽  
Force Equilibrium

By using the explicit solution of three-dimensional slope stability based on modification of normal stress distribution over the slip surface, the influence of assumption of the three-dimensional initial normal stress on the safety factor is investigated. The initial normal stress distribution over the 3D slip surface was assumed, and then it was modified by a function with 2 parameters to satisfy two force equilibrium conditions about two axes and one moment equilibrium condition around one axis. An iterative equation was derived that would yield a value to 3D safety factor. The values of three-dimensional safety factor of symmetrical slopes are computed with different assumptions of initial normal stresses. The computation results show that the influence of assumption of initial normal stress on the safety factor of symmetrical three-dimensional slopes is negligible because the maximum different value of the three-dimensional safety factor is below 5%.

Numerical Simulation Method Ascertaining Slope Stabilization Anti-Slippery Pile's Basic Parameters

2012 ◽  
Vol 594-597 ◽  
pp. 222-225
Author(s):  
Wen Juan Feng ◽  
Xiao Dong Ju ◽  
Zheng Sheng Zou
Keyword(s):  
Numerical Simulation ◽  
Safety Factor ◽  
Limit Equilibrium ◽  
Simulation Method ◽  
Simulation Software ◽  
Strength Reduction ◽  
Slope Stabilization ◽  
Limit Equilibrium Methods ◽  
Basic Parameters ◽  
Shear Strength Reduction

Although anti-slide pile take a key position in slope-treating measures, the method of designing is far from perfect. The methods used in actual projects are based on the rigid body limit equilibrium methods. There is a tendency to using numerical methods in the progress of pile-designing. The safety factor of landslide is calculated according to shear strength reduction theory in the numerical simulation software. Using the shearing forces on pile and the safety factor can ascertain the position of anti-slide piles, the area and distance of piles. For numerical simulation can well perform the simulation slope moving and the load on piles and can give a more reasonable designing.

scholarly journals Experimental and Numerical Investigation on the Stability of Loess Embankment Treated by Chemical Solution under Freezing-Thawing Conditions

2021 ◽  
Author(s):  
Hua Liu ◽  
Zelin Niu ◽  
Yuanhong Dong ◽  
Naifei Liu ◽  
Shuocheng Zhang
Keyword(s):  
Shear Strength ◽  
Safety Factor ◽  
Limit Equilibrium ◽  
Solution Concentration ◽  
Chemical Solution ◽  
Compression Index ◽  
Limit Equilibrium Methods ◽  
Novel Method ◽  
The Stability ◽  
Embankment Stability

Abstract In order to study the influence of chemical solution on the stability of loess embankment in seasonally frozen regions, the compression index, shear strength index and embankment safety factor of compacted loess fillings that were treated by different concentrations of chemical solution were analyzed through laboratory test and slope stability analysis program. The experimental results showed that the collapsible coefficients of remolded loess treated by different chemical solution will all increase which comparing the distilled water, and then will change again after freezing-thawing cycles (FTCs). The compression index of undisturbed loess will show regularity with the increase of chemical solution concentration. The shear strength of remolded loess also changed under the chemical solution and FTCs. Besides, simulation of the strength parameters by limit equilibrium methods showed that the safety factor of loess embankment with treatment of solution was significantly higher than that of untreated one, and the FTC would cause a further deterioration. The embankment stability improved after treated by chemical solution without considering seepage of rainwater. These results would provide a novel method to the problem of embankment stability related to environmental condition changes.

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.

Analysis of a rock slope with internal dilation

1984 ◽  
Vol 21 (4) ◽  
pp. 605-620 ◽  
Author(s):  
C. D. Martin ◽  
P. K. Kaiser
Keyword(s):  
Failure Mechanism ◽  
Rock Slope ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Three Dimensional ◽  
Back Analysis ◽  
Hydroelectric Project ◽  
Limit Equilibrium Methods ◽  
Slide Mass ◽  
Stability Of Slopes

A class of rock slope failures exists in which the mode of failure requires the existence or creation of internal shears to accommodate large internal slide mass distortion. These internal displacements are required to allow motion along the basal slip surface. This paper demonstrates that the more traditional limit equilibrium methods of analysis are often conservative when used to assess the stability of slopes with this failure mechanism. As a result, back analysis may overestimate the available shear resistance. A method of analysis capable of handling this failure mechanism was proposed by S. K. Sarma. A case history from the Revelstoke Hydroelectric Project, British Columbia, is used to demonstrate that these internal shears were required for movement to occur and that passive anchors inside the sliding rock mass can be used to improve the overall slope stability. No attempt is made to evaluate the actual factor of safety of the three-dimensional slide mass. Key words: rock slope, foliation shear, stability analysis, dilation, internal shears, passive anchors.

Prediction of Safety Factor for Slope Designed with Various Limit Equilibrium Methods

2011 ◽  
Vol 462-463 ◽  
pp. 611-615 ◽  
Author(s):  
Tariq Mohamed ◽  
Anuar Kasa ◽  
Taha Mohd Raihan
Keyword(s):  
Safety Factor ◽  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Limit Equilibrium ◽  
Calculated Data ◽  
Unit Weight ◽  
Inference System ◽  
Limit Equilibrium Methods ◽  
Neuro Fuzzy ◽  
The Stability

The purpose of this study is to predict the stability of slope using adaptive neuro fuzzy inference system (ANFIS). Based on limit equilibrium theory, four different methods of analyses, i.e. Morgenstern-Price, Janbu, Bishop and Ordinary were used to calculate the overall safety factor of various slope designs. Neuro-fuzzy inference system was used to map from a given input to an output. Important parameters such as height of slope (H), unit weight of soil (γ), angle of slope (θ), coefficient of cohesion (c) and internal angle of friction (ф) were used as the input parameters while overall safety factor was the output. ANFIS model to predict the stability of the slopes was generated from the calculated data. Results showed that factors of safety predicted using ANFIS agreed well with factors of safety calculated using Limit Equilibrium Methods (LEM).

scholarly journals Comparative analysis of large scale scenario-based landslides hazard zonation maps. A case study in Iasi City, Romania

2017 ◽  
Vol 19 (1) ◽  
pp. 145-154
Author(s):  
COMAN Cristina Magdalena ◽  
MANEA Sanda ◽  
OLINIC Ernest ◽  
BOȚI Ioan
Keyword(s):  
Comparative Analysis ◽  
Safety Factor ◽  
Large Scale ◽  
Deterministic Model ◽  
Hazard Analysis ◽  
Limit Equilibrium ◽  
Stability Factor ◽  
Northwestern Part ◽  
Engineering Software ◽  
Limit Equilibrium Methods

Large-scale landslides hazard analysis is based, among other methods, on the numerical evaluation of the safety factor using physical and mechanical parameters measured in the field. The safety factor is determined as the ratio between the forces acting in the favor of sliding phenomenon and the resistance of the earthen massive. The main purpose of the paper is to create two bi-dimensional models of landslides hazard assessment based on the estimation of the stability factor, under different degrees of soil saturation and considering different scenarios of seismic acceleration. Slope stability analysis allows the simultaneity of two exceptional loads such as saturation and earthquake. The first model follows the methodology provided by the national law. In this case, the safety factor is determined by applying limit equilibrium methods using specific geotechnical engineering software. The second model aims to create a deterministic model for safety factor assessment implemented in a GIS system. This one is based on the infinite slope model. The secondary objectives of the paper are: providing theoretical principles, attaining the comparative analysis between the methodologies mentioned above, identifying the critical points of the created models and the reciprocal validation of the results. The study area is a hilly area located in the NorthWestern part of the Iasi City, Romania. The geotechnical parameters were obtained from the laboratory tests carried out on samples taken from 22 boreholes. The geomorphological parameters resulted from the high quality digital elevation model with 1m resolution. The final maps representing the spatial distribution of the safety factor values are reclassified using a common scale. Similarity analysis of the results indicates a good mutual validation.

A simplified method for 3D slope stability analysis

2003 ◽  
Vol 40 (3) ◽  
pp. 675-683 ◽  
Author(s):  
Zuyu Chen ◽  
Hongliang Mi ◽  
Faming Zhang ◽  
Xiaogang Wang
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Upper Bound ◽  
Limit Equilibrium ◽  
Three Dimensional ◽  
Slope Stability Analysis ◽  
Accurate Solution ◽  
The Moment ◽  
3D Slope Stability ◽  
Force Equilibrium

This paper presents a simplified three-dimensional (3D) slope stability analysis method based on the limit equilibrium theory. The assumption involved in this method is of a parallel intercolumn force inclination, similar to Spencer's method in the two-dimensional (2D) area. It allows for the satisfaction of complete overall force equilibrium conditions and the moment equilibrium requirement about the main axis of rotation. The method has been proven to be numerically tractable for many practical problems. By combining this method with the 3D upper bound approaches, it is possible to bracket the accurate solution of a 3D slope stability analysis problem into a small range.Key words: slope stability analysis, three-dimensional analysis, limit equilibrium method, upper bound method.

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