Seismic passive resistance in soils for negative wall friction

2002 ◽  
Vol 39 (4) ◽  
pp. 971-981 ◽  
Author(s):  
Deepankar Choudhury ◽  
K S. Subba Rao
Keyword(s):  
Limit Equilibrium ◽  
Earth Pressure ◽  
Friction Angle ◽  
Wall Friction ◽  
Passive Earth Pressure ◽  
Passive Resistance ◽  
Pressure Coefficients ◽  
Logarithmic Spirals ◽  
Seismic Accelerations ◽  
The Individual

In the presence of pseudo-static seismic forces, passive earth pressure coefficients behind retaining walls were generated using the limit equilibrium method of analysis for the negative wall friction angle case (i.e., the wall moves upwards relative to the backfill) with logarithmic spirals as rupture surfaces. Individual density, surcharge, and cohesion components were computed to obtain the total minimum seismic passive resistance in soils by adding together the individual minimum components. The effect of variation in wall batter angle, ground slope, wall friction angle, soil friction angle, and horizontal and vertical seismic accelerations on seismic passive earth pressures are considered in the analysis. The seismic passive earth pressure coefficients are found to be highly sensitive to the seismic acceleration coefficients both in the horizontal and the vertical directions. The results are presented in graphical and tabular formats.Key words: seismic passive resistance, limit equilibrium, pseudo-static.

Formulation of Seismic Passive Resistance of Retaining Wall Backfilled with c-F Soil

2012 ◽  
Vol 3 (2) ◽  
pp. 15-24 ◽  
Author(s):  
Sima Ghosh
Keyword(s):  
Retaining Wall ◽  
Pressure Coefficient ◽  
Earth Pressure ◽  
Friction Angle ◽  
Wall Friction ◽  
Unit Weight ◽  
Passive Resistance ◽  
Angle Of Internal Friction ◽  
Variation Of Parameters ◽  
Wide Range

Knowledge of passive resistance is extremely important and it is the basic data required for the design of geotechnical structures like the retaining wall moving towards the backfill, the foundations, the anchors etc. An attempt is made to develop a formulation for the evolution of seismic passive resistance of a retaining wall supporting c-F backfill using pseudo-static method. Considering a planar rupture surface, the formulation is developed in such a way so that a single critical wedge surface is generated. The variation of seismic passive earth pressure coefficient are studied for wide range of variation of parameters like angle of internal friction, angle of wall friction, cohesion, adhesion, surcharge, unit weight of the backfill material, height and seismic coefficients.

Passive earth-pressure coefficients by upper-bound numerical limit analysis

2011 ◽  
Vol 48 (5) ◽  
pp. 767-780 ◽  
Author(s):  
Armando N. Antão ◽  
Teresa G. Santana ◽  
Mário Vicente da Silva ◽  
Nuno M. da Costa Guerra
Keyword(s):  
Upper Bound ◽  
Limit Analysis ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Earth Pressure ◽  
Wall Friction ◽  
Passive Earth Pressure ◽  
Upper Bound Theorem ◽  
Pressure Coefficients ◽  
Bound Theorem

A three-dimensional (3D) numerical implementation of the limit analysis upper-bound theorem is used to determine passive horizontal earth-pressure coefficients. An extension technique allowing determination of the 3D passive earth pressures for any width-to-height ratios greater than 7 is presented. The horizontal passive earth-pressure coefficients are presented and compared with solutions published previously. Results of the ratio between the 3D and two-dimensional horizontal passive earth-pressure coefficients are shown and found to be almost independent of the soil-to-wall friction ratio. A simple equation is proposed for calculating this passive earth-pressure ratio.

Seismic passive earth pressure coefficients for sands

2001 ◽  
Vol 38 (4) ◽  
pp. 876-881 ◽  
Author(s):  
Jyant Kumar
Keyword(s):  
Limit Equilibrium ◽  
Earth Pressure ◽  
Logarithmic Spiral ◽  
Failure Surface ◽  
Passive Earth Pressure ◽  
Pressure Coefficients ◽  
Straight Line ◽  
Earth Pressures ◽  
Planar Failure ◽  
Seismic Forces

By taking the failure surface as a combination of the arc of a logarithmic spiral and a straight line, passive earth pressure coefficients in the presence of horizontal pseudostatic earthquake body forces have been computed for an inclined wall placed against cohesionless backfill material. The presence of seismic forces induces a considerable reduction in the passive earth resistance. The reduction increases with an increase in the magnitude of the earthquake acceleration. The effect becomes more predominant for loose sands. The obtained results compared well with those reported in the literature using curved failure surfaces. However, the results available in the literature on the basis of a planar failure surface are found to predict comparatively higher passive resistance.Key words: earth pressures, earthquakes, limit equilibrium, plasticity, retaining walls, sands.

scholarly journals Analysis of passive earth pressure modification due to seepage flow effects

2018 ◽  
Vol 55 (5) ◽  
pp. 666-679 ◽  
Author(s):  
Z. Hu ◽  
Z.X. Yang ◽  
S.P. Wilkinson
Keyword(s):  
Limit Equilibrium ◽  
Retaining Wall ◽  
Reaction Force ◽  
Earth Pressure ◽  
Failure Surface ◽  
Friction Angle ◽  
Seepage Flow ◽  
Fourier Series Expansion ◽  
Passive Earth Pressure ◽  
Interface Friction

Using an assumed vertical retaining wall with a drainage system along the soil–structure interface, this paper analyses the effect of anisotropic seepage flow on the development of passive earth pressure. Extremely unfavourable seepage flow inside the backfill, perhaps due to heavy rainfall, will dramatically increase active earth pressure while reducing passive earth pressure, thus increasing the probability of instability of the retaining structure. A trial and error analysis based on limit equilibrium is applied to identify the optimum failure surface. The flow field is computed using Fourier series expansion, and the effective reaction force along the curved failure surface is obtained by solving a modified Kötter equation considering the effect of seepage flow. This approach correlates well with other existing results. For small values of both the internal friction angle and interface friction angle, the failure surface can be appropriately simplified with a planar approximation. A parametric study indicates that the degree of anisotropic seepage flow affects the resulting passive earth pressure. In addition, incremental increases in the effective friction angle and interface friction angle both lead to an increase in passive earth pressure.

New approach for analysis of cantilever sheet pile with line load

2006 ◽  
Vol 43 (5) ◽  
pp. 540-549 ◽  
Author(s):  
Deepankar Choudhury ◽  
Shailesh Singh ◽  
Shubhra Goel
Keyword(s):  
Penetration Depth ◽  
Limit Equilibrium ◽  
Earth Pressure ◽  
Friction Angle ◽  
Wall Friction ◽  
Horizontal Line ◽  
Sheet Pile ◽  
Free Standing ◽  
Line Load ◽  
Sheet Pile Wall

Free-standing cantilever sheet pile walls in cohesionless soils subjected to horizontal line load have traditionally been analyzed assuming full active and passive earth pressure mobilization on the sides of the embedded portion of the wall. In the conventional analysis, the vertical equilibrium of forces is not checked and the effect of the wall friction angle is neglected because of the assumption of a smooth wall. In the present study, the limit equilibrium method has been used to estimate the minimum penetration depth required for a free-standing cantilever sheet pile wall subjected to horizontal line load, by considering the effect of wall friction angle, thereby satisfying all equilibrium conditions and considering the partial mobilization of earth pressures depending on the type and magnitude of the wall movement. The variation of earth pressure mobilization has been taken as a function of the displacement (rotation about both the top and the bottom) of the cantilever sheet pile wall, which in turn also governs the mobilized friction angles. A comparison has been made between the results of penetration depths obtained by the present study and those obtained by existing conventional solutions. New design values in nondimensional form are proposed.Key words: wall friction angle, partial earth pressure mobilization, cohesionless soil, penetration depth, equilibrium equations, displacement.

Determination of passive earth pressure coefficients using limit equilibrium approach coupled with the Kötter equation

2015 ◽  
Vol 52 (9) ◽  
pp. 1241-1254 ◽  
Author(s):  
Mrunal A. Patki ◽  
J.N. Mandal ◽  
D.M. Dewaikar
Keyword(s):  
Limit Equilibrium ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Failure Surface ◽  
Passive Earth Pressure ◽  
Pressure Coefficients ◽  
Composite Failure ◽  
Equilibrium Approach ◽  
The Moment

A numerical method is developed to evaluate the passive earth pressure coefficients for an inclined rigid retaining wall resting against a horizontal cohesionless backfill. A composite failure surface comprises a log spiral, and its tangent is assumed in the present study. The unique failure surface is identified based on the limit equilibrium approach coupled with the Kötter equation (published in 1903). Force equilibrium conditions are used to evaluate the magnitude of the passive thrust, whereas the moment equilibrium condition is employed to determine the location of the passive thrust. The distinctive feature of the present study is that no assumption is required to be made regarding the point of application of the passive thrust, which would otherwise be an essential criterion with respect to the several limit equilibrium based investigations available in the literature. The passive earth pressure coefficients, Kpγ, are evaluated for various values of soil frictional angle [Formula: see text], wall frictional angle δ, and wall inclination angle λ, and compared with the existing results.

Limit equilibrium computation of dynamic passive earth pressure

1995 ◽  
Vol 32 (3) ◽  
pp. 481-487 ◽  
Author(s):  
Ernest E. Morrison Jr. ◽  
Robert M. Ebeling
Keyword(s):  
Limit Equilibrium ◽  
Pressure Coefficient ◽  
Earth Pressure ◽  
Failure Surface ◽  
Friction Angle ◽  
Passive Earth Pressure ◽  
Equilibrium Equations ◽  
Cohesionless Soils ◽  
Earth Pressures ◽  
Earth Pressure Coefficient

Few solution techniques exist for the determination of pseudostatic dynamic passive earth pressures for cohesionless soils. The widely accepted Mononobe–Okabe equation can result in the computing of unconservative values if the wall interface friction angle is greater than half the soil internal friction angle. As an alternate solution, equilibrium equations were formulated assuming a log spiral failure surface, and a research computer program was written to calculate the dynamic passive earth pressure coefficient. The primary purpose of this paper is to present a comparison of results obtained using the Mononobe–Okabe equation with those obtained using the log spiral formulation. Key words : pseudostatic, dynamic, passive earth pressure.

Determination of passive earth pressure coefficients by the method of triangular slices

2000 ◽  
Vol 37 (2) ◽  
pp. 485-491 ◽  
Author(s):  
Da-Yong Zhu ◽  
Qihu Qian
Keyword(s):  
Limit Equilibrium ◽  
Pressure Coefficient ◽  
Earth Pressure ◽  
Limit Equilibrium Method ◽  
Passive Earth Pressure ◽  
Pressure Coefficients ◽  
Principle Of Optimality ◽  
Force Coefficients ◽  
Equilibrium Method

A new procedure is proposed for determination of passive earth pressure coefficients using triangular slices within the framework of the limit equilibrium method. The potential sliding mass is subdivided into a series of triangular slices, rather than vertical slices as usual, with inclinations of the slice bases to be determined. The forces between two adjacent slices (interslice forces) are expressed in terms of interslice force coefficients, and recursive equations for solving interslice coefficients are derived. By using the principle of optimality, the critical inclinations of slice bases, minimum interslice force coefficients, and passive earth pressure coefficients are determined. A form of function for describing the distribution of interslice force inclination (interslice force function) is suggested and the scaling parameter contained in the function is determined by satisfying the moment equilibrium condition for the final sliding mass. Comparisons are made with other accepted methods and tables for passive earth pressure coefficients are presented for practical use.Key words: passive earth pressure coefficient, retaining walls, limit equilibrium method, the principle of optimality.

Pseudo-Dynamic Evolution of Seismic Passive Earth Force and Pressure Behind Retaining Wall

2011 ◽  
Vol 2 (2) ◽  
pp. 1-15
Author(s):  
Sima Ghosh
Keyword(s):  
Dynamic Method ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Friction Angle ◽  
Wall Friction ◽  
Dynamic Evolution ◽  
Linear Variation ◽  
Passive Earth Pressure ◽  
Non Linear ◽  
Surface Inclination

This paper presents a detailed study on the seismic passive earth pressure behind a non-vertical cantilever retaining wall supporting inclined backfill, using pseudo-dynamic method. In addition to the consideration of wall and backfill surface inclination, the soil friction angle, wall friction angle, and both horizontal and vertical seismic coefficients are taken into account. From the obtained results, a non-linear variation of passive earth pressure along the height of the wall is observed. The results compare well with the existing values in research.

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