Comparative analyses of finite element and limit-equilibrium methods for heavily fractured rock slopes

2020 ◽  
Vol 129 (1) ◽  
Author(s):  
Tümay Kadakci Koca ◽  
M Yalçin Koca
Keyword(s):  
Finite Element ◽  
Fractured Rock ◽  
Limit Equilibrium ◽  
Rock Slopes ◽  
Comparative Analyses ◽  
Limit Equilibrium Methods

scholarly journals Error Source Analysis and Precision Assessment of Limit Equilibrium Methods for Rock Slopes

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaofan An ◽  
Ning Li ◽  
Peng Zhang ◽  
Wenbo Sun
Keyword(s):  
Finite Element ◽  
Evaluation Method ◽  
Progressive Failure ◽  
Limit Equilibrium ◽  
Influence Factors ◽  
Source Analysis ◽  
Rock Slopes ◽  
Error Source ◽  
Sliding Surfaces ◽  
Limit Equilibrium Methods

The approximate assumptions of limit equilibrium methods are the fundamental cause of the deviation between their calculation results and actual situation. This study proposes a new finite-element evaluation method to reflect the progressive failure characteristics of rock slopes. By comparing the results of limit equilibrium and finite-element methods, the influence factors of stability for planar landslides are systematically studied. The factors include the plastic parameters of sliding surfaces in progressive failure, the elastic parameters of sliding mass, the elastic deformation of sliding beds, and excavation stress release. Moreover, the stress distribution rules on sliding surfaces and the diversity of safety factors are explored. Finally, the error source and calculation accuracy of the limit equilibrium method in slope analysis are obtained. The study provides scientific references for analyzing and evaluating the stability of such slopes.

scholarly journals Factor of Safety Reduction Factors for Accounting for Progressive Failure for Earthen Levees with Underlying Thin Layers of Sensitive Soils

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Adam J. Lobbestael ◽  
Adda Athanasopoulos-Zekkos ◽  
Josh Colley
Keyword(s):  
Finite Element ◽  
Strain Softening ◽  
Progressive Failure ◽  
Limit Equilibrium ◽  
Thin Layers ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Limit Equilibrium Methods ◽  
The Stability ◽  
Reduction Factors

The effects of progressive failure on flood embankments with underlying thin layers of soft, sensitive soils are investigated. Finite element analysis allows for investigation of strain-softening effects and progressive failure in soft and sensitive soils. However, limit equilibrium methods for slope stability analysis, widely used in industry, cannot capture these effects and may result in unconservative factors of safety. A parametric analysis was conducted to investigate the effect of thin layers of soft sensitive soils on the stability of flood embankments. A flood embankment was modeled using both the limit equilibrium method and the finite element method. The foundation profile was altered to determine the extent to which varying soft and sensitive soils affected the stability of the embankment, with respect to progressive failure. The results from the two methods were compared to determine reduction factors that can be applied towards factors of safety computed using limit equilibrium methods, in order to capture progressive failure.

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.

Stability Analyses of Western Slopes in Jointed Rock Masses for GuangYang Highway

2011 ◽  
Vol 368-373 ◽  
pp. 234-240
Author(s):  
Shu Li Wang ◽  
Man Gen Mu ◽  
Ran Wang ◽  
Wen Bo Cui
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Limit Equilibrium ◽  
Western Slope ◽  
Seismic Load ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Limit Equilibrium Methods ◽  
The Stability ◽  
Element Method

This paper presents the results of a study on a joint slope deformation affecting the western slope of the GuangYang highway (YangQuan, China). Fieldwork identified the ongoing deformational process and assisted in defining its mechanisms, evolution and controlling factors. Here we discuss how to use limit equilibrium methods to calculate the behavior of slopes and to use the finite element analysis to evaluate the stability, displacements of slopes and soil-slope stabilization interaction. The finite element method with shear strength reduction (SSR) technique is explained in Phase2D. This method is effective for the prediction of the stability of slope. Based on numerical comparisons between the limit equilibrium methods and finite element method, it is suggested that the finite element method with SSR technique is a reliable and maybe unique approach to evaluate the slope stability. The paper also took into account effectiveness of the large rain and seismic load. The results of the numerical analysis are consistent with the observed slope surface evidence.

scholarly journals Towards a simple and reliable method for calculating the uplift capacity of plate anchors in sand

2020 ◽  
Author(s):  
Anamitra Roy ◽  
Shiao Huey Chow ◽  
Conleth D O'Loughlin ◽  
Mark F. Randolph
Keyword(s):  
Finite Element ◽  
Limit Equilibrium ◽  
Finite Element Simulations ◽  
Surface Model ◽  
Large Set ◽  
Uplift Capacity ◽  
Bounding Surface ◽  
Limit Equilibrium Methods ◽  
Current Limit ◽  
Plate Anchors

his paper investigates the uplift capacity of horizontal plate anchors in sand through finite element analyses and centrifuge experiments. Finite element simulations adopt a sophisticated bounding surface plasticity model that accounts for stress and density dependent behaviour, as well as loading and fabric related anisotropic effects in sands. Failure mechanisms at peak anchor capacity show that failure occurs progressively, with a marked decrease in mobilised friction angle within the shear bands close to the anchor edge. Numerical simulations of a large set of centrifuge experiments on rectangular, strip and circular plates at different relative densities and stress levels are in good agreement for dense conditions, but perform poorer for loose conditions due mainly to the open cone yield surface in the bounding surface model. Equivalent comparisons with current limit equilibrium methods highlight the challenges in direct application of element level strength equations. Finally, the paper proposes a modified limit equilibrium solution based on a ‘rigid-block’ failure mechanism extending to soil surface, but with anchor factors that encompass the results from the finite element simulations. The modified solution provides a higher level of agreement with results from a large database of plate and pipeline test data than existing limit equilibrium methods.

scholarly journals Analysis of embankment slope stability: the comparison of finite element limit analysis with limit equilibrium methods

2019 ◽  
Vol 270 ◽  
pp. 02004
Author(s):  
Kongkit Yingchaloenkitkhajorn
Keyword(s):  
Finite Element ◽  
Slope Stability ◽  
Limit Analysis ◽  
Limit Equilibrium ◽  
Slope Angle ◽  
Friction Angle ◽  
Volume Element ◽  
Stability Number ◽  
Limit Equilibrium Methods ◽  
Embankment Slope

This paper presented the analysis of embankment slope stability by considering the problem of embankment slope stability with special effects that it was filled with sand and was placed on purely cohesive clay. The finite element limit analysis of two-dimensional plane strain was employed to analyze the stability of this problem. The embankment slope height (H), the depth factors (d/H) and the embankment slope angle (β) for the finite element limit analysis of sand was modeled as a volume element with the properties of Mohr-Coulomb material in drained condition. And the clay was modeled as a volume element with the properties of Tresca material in undrained condition where the parameters were soil unit weight (γ), undrained shear strength (su) and friction angle (φ′). Parametric studies consisted of three dimensionless variables including depth factors (d/H), friction angle (φ′) and embankment slope angle (β). Results were summarized in the form of the dimensionless stability number (su/γH(FS)) and the design chart and application were presented. In addition, the comparison of the solution of stability number with the limit equilibrium methods and the failure mechanisms were also proposed in this paper.

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.

Sign in / Sign up

Export Citation Format

Share Document