Factor of safety of slope stability from deformation energy

2018 ◽  
Vol 55 (2) ◽  
pp. 296-302 ◽  
Author(s):  
Shiguo Xiao ◽  
Wei Dong Guo ◽  
Jinxiu Zeng
Keyword(s):  
Shear Strength ◽  
Factor Of Safety ◽  
Plastic Material ◽  
Limit Equilibrium ◽  
Deformation Energy ◽  
Simple Expression ◽  
Shear Stresses ◽  
Limit Equilibrium Methods ◽  
Coulomb Failure Criterion ◽  
Elastic Plastic Material

The factor of safety of a slope (Fs) is invariably assessed using methods underpinned by moment, force, and (or) shear strength equilibrium concerning slip surfaces. Each method inherently embeds some form of limitations, despite being popularly adopted in practice. In this paper, a new Fs is devised using the ratio of ultimate energy (eu, upon sliding) over accumulated “elastic” energy. The Fs is then reduced to a simple expression of the power to shear stress and shear strength, by taking soil as an elastic–plastic material obeying the Mohr–Coulomb failure criterion. This expression empowers significant efficacy in gaining the factor of safety (without involving energy or directions of shear stresses). The Fs values were calculated for three typical slopes concerning various mechanical properties (dilation, Poisson’s ratio, and shear modulus) and effective computational strategies. All of the Fs values (to a congruous accuracy of available methods) were obtained in less than 1% the time of conventional numerical analyses. The proposed Fs, equally applicable to limit equilibrium methods, may be utilized in practice to expedite slope design.

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.

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.

The 2001 R.M. Hardy Lecture: The limits of limit equilibrium analyses

2003 ◽  
Vol 40 (3) ◽  
pp. 643-660 ◽  
Author(s):  
John Krahn
Keyword(s):  
Finite Element ◽  
Factor Of Safety ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Geotechnical Engineering ◽  
Software Tools ◽  
Great Promise ◽  
Engineering Practice ◽  
Stability Factor ◽  
Limit Equilibrium Methods

Limit equilibrium types of analysis have been in use in geotechnical engineering for a long time and are now used routinely in geotechnical engineering practice. Modern graphical software tools have made it possible to gain a much better understanding of the inner numerical details of the method. A closer look at the details reveals that the limit equilibrium method of slices has some serious limitations. The fundamental shortcoming of limit equilibrium methods, which only satisfy equations of statics, is that they do not consider strain and displacement compatibility. This limitation can be overcome by using finite element computed stresses inside a conventional limit equilibrium framework. From the finite element stresses both the total shear resistance and the total mobilized shear stress on a slip surface can be computed and used to determine the factor of safety. Software tools that make this feasible and practical are now available, and they hold great promise for advancing the technology of analyzing the stability of earth structures.Key words: limit equilibrium, stability, factor of safety, finite element, ground stresses, slip surface.

scholarly journals Strain-dependent slope stability

2020 ◽  
Vol 15 (11) ◽  
pp. 3111-3119
Author(s):  
Kornelia Nitzsche ◽  
Ivo Herle
Keyword(s):  
Slope Stability ◽  
Failure Modes ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Shear Stresses ◽  
Safety Factors ◽  
Limit Equilibrium Methods ◽  
Hydraulic Conditions ◽  
Stress States ◽  
Strain Dependent

Abstract The state of equilibrium of a slope is usually interpreted and expressed by safety factors based on calculations with limit equilibrium methods. Different stress states, failure modes and hydraulic conditions in sections along a slip surface affect the development of shear stresses during slope movement. Moreover, a post-peak softening of the shear strength can have a pronounced impact. As a consequence of the latter effect, the mobilization of the shear resistance along the slip surface is non-uniform and the safety of the slope can be overestimated or underestimated. In the presented paper, an algorithm is proposed to capture the strain-dependent slope stability. The approach is illustrated by means of a calculation example for a slope with a planar slip surface where a block sliding is assumed.

Earthquake Impact Analyses on Slopes Using Finite Element and Limit Equilibrium Methods

2010 ◽  
Vol 163-167 ◽  
pp. 3868-3871
Author(s):  
Yu Hwang Ong ◽  
Anuar Kasa ◽  
Zamri Chik ◽  
Taha Mohd Raihan
Keyword(s):  
Finite Element ◽  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Friction Angle ◽  
Determine Factor ◽  
Earthquake Activity ◽  
Limit Equilibrium Methods ◽  
Dynamic Analyses ◽  
Cut Slopes ◽  
Steep Slopes

The objective of this research is to determine factor of safety for various cut slopes under the influence of earthquake activity. Finite element method was used to generate initial static stress condition and run dynamic analyses of the cut slopes. Factor of safety was then calculated using limit equilibrium method. Both sand and clay were analyzed in this study. The results show that steep slopes with initial safety factor of 1.5 are capable to sustain earthquake magnitude of 0.25g due to high shear strength of the soil. However, slopes with friction angle less than 21º for sand and cohesion value less than 38 kPa for clay are not stable. This shows that earthquake loading should be considered in the design of cut slopes in Malaysia.

scholarly journals Geotechnical characterisation and back analysis of a landslide in marl deposit: A case study of Algiers Sahel (coast), Algeria

2020 ◽  
Vol 62 (4) ◽  
Author(s):  
M Filali ◽  
A Nechnech ◽  
J de Rosa ◽  
H Gadouri ◽  
B Meziani
Keyword(s):  
Shear Strength ◽  
Limit Equilibrium ◽  
Back Analysis ◽  
Test Results ◽  
Limit Equilibrium Methods ◽  
Laboratory Test Results ◽  
Geotechnical Investigations ◽  
The Stability ◽  
Low Shear

The purposeof this study isto present the results of geotechnical investigations and landslide analysis in a marl deposit at the Sahel (coast) of Algiers in northern Algeria, where many landslides take place in the Plaisancian marls, particularly following rainfall periods each year, causing severe damage to infrastructures and buildings. The physico-mechanical characteristics of the soils obtained from three different sites (El-Achour, Daly-Brahim and Ouled-Fayet) were analysed to identify the mechanism of these landslides. In the study, the laboratory test results providing grain-size distribution, Atterberg limits, water content, shear strength, and compressibility were analysed. The findings showed that, although the soils were characterised by slightly higher plasticity at Ouled-Fayet, they were generally homogeneous in the studied sites. The upper soils, generally weathered, exhibited low shear strength parameters, which are lower than the undisturbed formation beneath. The stability analysis based on limit equilibrium methods (LEM) showed the significant influence of pore water pressures on slope stability, suggesting that the weathered soils are prone to instability processes due to the effect of long rainy periods.

scholarly journals Performance of cement-stabilized weak subgrade for highway embankment construction in Southeast Nigeria

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Chukwuka Ifediniru ◽  
Nnamdi E. Ekeocha
Keyword(s):  
Shear Strength ◽  
Factor Of Safety ◽  
Shear Failure ◽  
Cement Content ◽  
Limit Equilibrium ◽  
Southeastern Nigeria ◽  
Subgrade Soil ◽  
Clayey Silt ◽  
Stabilized Soil ◽  
Strength Improvement

AbstractSoils with poor shear strength and high compressibility underlie the wetlands of southern Nigeria. They are susceptible to intolerable settlements and account for greater than 60% of the soils in the region. While requiring embankments for any infrastructure construction, these weak soils pose significant threat to the construction and service life of highway pavements in southeastern Nigeria. Therefore, this research investigates shear strength improvement of a highway embankment’s weak subgrade soil after mass stabilization of soil with 6 and 10% Portland cement. The factor of safety against shear failure of the embankment was analyzed for un-stabilized subgrade and then cement-stabilized subgrade. The analysis was carried out for embankment heights of 4, 5, 6 and 7 m using the limit equilibrium method. Thick soft clayey silt with Cu range of 9 to 15 kPa underlay the embankment, upon improvement, the Cu of 154 and 208 kPa was obtained for 6 and 10% stabilization respectively. The FoS for the embankment on Un-stabilized soil ranged from 0.88 for a 7 m embankment to 1.2 for a 4 m embankment. The FoS after mass stabilization of 1 to 5 m soil ranged between 1.77 and 5.22 for the different embankment heights. Stability was better improved as depth of mass stabilization and cement content increased. A linear relationship was observed to exist between the cement content, strength of the improved soils, stabilization depth and the factor of safety.

Sign in / Sign up

Export Citation Format

Share Document