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.

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.

Analysis of progressive deformation of the Edmonton Convention Centre excavation

1987 ◽  
Vol 24 (3) ◽  
pp. 430-440 ◽  
Author(s):  
D. H. Chan ◽  
N. R. Morgenstern
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Softening ◽  
Progressive Failure ◽  
Field Measurements ◽  
Shear Zones ◽  
Element Model ◽  
Progressive Deformation ◽  
Element Analysis ◽  
The Stability

A finite element analysis was performed of the deformations observed during the excavation of the Edmonton Convention Centre. Local geology in the Edmonton area consists of layers of shale with weak bentonite seams overlain by glacial deposits. The presence of the bentonite seams, which possess strain-softening characteristics, controls the stability of the excavation, which is located in a valley wall. To simulate the influence of the bentonite seams a strain-softening finite element model is used to estimate the amount of deformation in the foundation of the excavation. Field measurements indicated that localized progressive straining had occurred during the excavation process, and substantial heave of the foundation floor was observed. The finite element results show progressive deformation of the excavation and propagation of shear zones. Good agreement between the finite element results and the field observations is obtained. Key words: progressive failure, strain softening, finite element analysis, shear band, excavation stability.

Progressive failure of the Carsington Dam: a numerical study

1992 ◽  
Vol 29 (6) ◽  
pp. 971-988 ◽  
Author(s):  
Z. Chen ◽  
N. R. Morgenstern ◽  
D. H. Chan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Factor Of Safety ◽  
Progressive Failure ◽  
Limit Equilibrium ◽  
Equilibrium Analysis ◽  
Element Analysis ◽  
Limit Equilibrium Analysis ◽  
The Finite Element Analysis ◽  
Yellow Clay

The mechanism of progressive failure is well understood as one which involves nonuniform straining of a strain-weakening material. Traditional limit equilibrium analysis cannot be used alone to obtain a rational solution for progressive failure problems because the deformation of the structure must be taken into account in the analysis. The failure of the Carsington Dam during construction in 1984 has been attributed to progressive failure of the underlying yellow clay and the dam core materials. The dam was monitored extensively prior to failure, and an elaborate geotechnical investigation was undertaken after failure. The limit equilibrium analysis indicated that the factors of safety were over 1.4 using peak strength of intact clay material or 1.2 based on reduced strength accounting for preshearing of the yellow clay layer. Factors of safety were found to be less than unity if residual strengths were used. The actual factor of safety at failure was, of course, equal to one. By using the finite element analysis with strain-weakening models, the extent and degree of weakening along the potential slip surface were calculated. The calculated shear strength was then used in the limit equilibrium analysis, and the factor of safety was found to be 1.05, which is very close to the actual value of 1.0. More importantly, the mechanism of failure and the initiation and propagation of the shear zones were captured in the finite element analysis. It was also found that accounting explicitly for pore-water pressure effects using the effective stress approach in the finite element and limit equilibrium analyses provides more realistic simulations of the failure process of the structure than analyses based on total stresses. Key words : progressive failure, strain softening, finite element analysis, dams.

Low-order mixed finite element analysis of progressive failure in pressure-dependent materials within the framework of the Cosserat continuum

2017 ◽  
Vol 34 (2) ◽  
pp. 251-271 ◽  
Author(s):  
Hongxiang Tang ◽  
Yuhui Guan ◽  
Xue Zhang ◽  
Degao Zou
Keyword(s):  
Finite Element ◽  
Strain Softening ◽  
Progressive Failure ◽  
Mixed Finite Element ◽  
Failure Process ◽  
Cosserat Continuum ◽  
Element Analysis ◽  
Content Type ◽  
Engineering Problems ◽  
Low Order

Purpose This paper aims to develop a finite element analysis strategy, which is suitable for the analysis of progressive failure that occurs in pressure-dependent materials in practical engineering problems. Design/methodology/approach The numerical difficulties stemming from the strain-softening behaviour of the frictional material, which is represented by a non-associated Drucker–Prager material model, is tackled using the Cosserat continuum theory, while the mixed finite element formulation based on Hu–Washizu variational principle is adopted to allow the utilization of low-order finite elements. Findings The effectiveness and robustness of the low-order finite element are verified, and the simulation for a real-world landslide which occurred at the upstream side of Carsington embankment in Derbyshire reconfirms the advantages of the developed elastoplastic Cosserat continuum scheme in capturing the entire progressive failure process when the strain-softening and the non-associated plastic law are involved. Originality/value The permit of using low-order finite elements is of great importance to enhance computational efficiency for analysing large-scale engineering problems. The case study reconfirms the advantages of the developed elastoplastic Cosserat continuum scheme in capturing the entire progressive failure process when the strain-softening and the non-associated plastic law are involved.

Finite Element Analysis of Quench Propagation Velocity in Bi-2223/Ag Superconducting Multifilamentary Tape

2007 ◽  
Vol 546-549 ◽  
pp. 1931-1934
Author(s):  
Chun Li Wu ◽  
Hai Liang Yang
Keyword(s):  
Finite Element ◽  
Propagation Velocity ◽  
Operating Temperature ◽  
Superconducting Magnet ◽  
Experimental Result ◽  
The Finite Element Method ◽  
Analysis Model ◽  
Element Analysis ◽  
The Stability ◽  
Quench Propagation

Quench propagation velocity is an important parameter to the stability and protection issues of superconducting magnet. In this paper, the finite element method (FEM) numerical simulation of quench propagation velocity has been performed for using the powerful analysis software COSMOS by establishing a suitable thermal analysis model of Bi-2223/Ag superconducting multifilamentary tape. The effects of quench energy and operating temperature on the quench propagation velocity have been studied. The analysis shows that the simulation result basically coincides with the experimental result.

Numerical Simulation of Rock Stability under Dynamic Blasting Load

2007 ◽  
Vol 353-358 ◽  
pp. 1041-1044
Author(s):  
Fu Kun Xiao ◽  
Guang Yi Sun ◽  
Li Hui Tian
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Time Dynamic ◽  
Rock Stability ◽  
Dynamic Stress Field ◽  
The Stability ◽  
Short Time ◽  
Blasting Load

In order to study the effect of blast shake on the stability of tunnel during mining process, finite element analysis software for rock and soil engineering is used to simulate the effect of blasting shake. In the simulation, a short-time dynamic load is applied to the rock in the blasting zone. Dynamic stress field in the rock mass and distortion in the surface of the tunnel are calculated with the finite-element method. Equivalent displacement method is utilized to determine the amount of sudden applied load, the actuation duration and the range of action. Consequently, the maximum critical explosive content at the critical shake speed of rock mass can be defined.

scholarly journals Design and strength analysis of C-hook for load using the finite element method

2020 ◽  
Vol 313 ◽  
pp. 00034
Author(s):  
Pavol Lengvarský ◽  
Martin Mantič ◽  
Róbert Huňady
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Strength Analysis ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Deformation State ◽  
The Finite Element Analysis ◽  
Stress And Deformation ◽  
The Stability

The special type of C-hook is investigated in this paper. The C-hook is designed to carry a special load, where is not possible to use classical hooks or chain slings. The designed hook is consisted of two arms that ensure the stability of the load being carried. The finite element analysis is performed for the control of the stress and deformation state in the whole hook. The fatigue analysis is performed for the check of a lifetime of C-hook.

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.

The stability of embankments reinforced with steel

1993 ◽  
Vol 30 (5) ◽  
pp. 768-780 ◽  
Author(s):  
R. Kerry Rowe ◽  
Brian L.J. Mylleville
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Limit Equilibrium ◽  
Soft Soil ◽  
Potential Yield ◽  
Element Analysis ◽  
Worked Example ◽  
Steel Strips ◽  
The Stability ◽  
Embankment Stability

The undrained behaviour of embankments constructed on soft cohesive deposits is examined for the case where the embankment is reinforced using steel strips. A finite-element analysis that considers plastic failure of the fill and the foundation, pullout of steel strips, and potential yield of the reinforcement is used to demonstrate how steel reinforcement can improve embankment stability. The effect of strip spacing on the mode of failure and embankment stability is examined for a range of soil strength profiles that involve an increase in undrained shear strength with depth. A simple approach for the analysis of steel-reinforced embankments is proposed and illustrated by means of a worked example. A design based on these simple considerations of bearing capacity and limit equilibrium is then checked against the results of a full finite-element analysis of the problem and found to be slightly conservative. Key words : reinforcement, steel strips, finite element, limit equilibrium, soft soil, undrained stability.

Progressive Failure of Offshore Slopes due to Construction in Upslope Areas

2015 ◽  
Author(s):  
Rajib Dey ◽  
Bipul Hawlader ◽  
Chen Wang
Keyword(s):  
Large Scale ◽  
Strain Softening ◽  
Progressive Failure ◽  
Limit Equilibrium ◽  
Shear Bands ◽  
Submarine Landslides ◽  
Limit Equilibrium Methods ◽  
Triggering Factor ◽  
Potential Failure ◽  
Clay Layers

Human activities such as construction loading in upslope areas could be a potential triggering factor for many offshore landslides such as the 1979 Nice landslide. Post-slide investigations show that the existence of marine sensitive clay layers might be one of the potential causes of many large-scale submarine landslides. In this paper, a finite element (FE) modeling technique is developed to analyze the failure of a slope in undrained condition. Nonlinear strain softening behaviour of undrained shear strength of marine sensitive clays is incorporated in the FE analysis. Strain localization in narrow zones (i.e. shear bands) could be successfully simulated. The formation of shear bands and their propagation could explain some potential failure mechanisms. The FE results show that large-scale catastrophic failure of submarine slopes might have occurred due to shear band propagation through strain softening clay layers, which cannot be explained using the traditional limit equilibrium methods for slope stability analysis. Effects of different factors, such as thickness of the marine clay layer and its sensitivity, on stability of submarine slope are also examined.

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