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.

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.

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.

scholarly journals Study on Passive Earth Pressure of Retaining Wall in Transversely Isotropic Soil

2020 ◽  
Vol 143 ◽  
pp. 01020
Author(s):  
Tao Chen ◽  
Chao Chen ◽  
Fengting Guan ◽  
Ruoyang Zhou
Keyword(s):  
Limit Equilibrium ◽  
Retaining Wall ◽  
Transverse Isotropy ◽  
Earth Pressure ◽  
Transversely Isotropic ◽  
Least Square Method ◽  
Least Square ◽  
Passive Earth Pressure ◽  
Principal Stress Direction ◽  
Tensor Theory

Based on the fabric tensor theory and the principle of least square method, the method of block processing in the same model to explore the variation of the passive earth pressure of the transversely isotropic soil was used in the study. At the same time, primary displacement application and multiple displacement application were applied to change the angle between the large principal stress direction of the filling and the normal direction of the deposition surface to obtain the new strength parameters ci and φi of each block after the model was divided and additionally analyzing the variation of the anisotropic passive earth pressure. The study shows: 1.Considering the transverse isotropy of the soil and reaching the limit equilibrium, the passive earth pressure of the soil after multiple displacement application is not only smaller than that after primary displacement application but also closed to the theoretical solution of Coulomb’s earth pressure; 2.When the soil is inclined, the anisotropy is significant when compared with the horizontal direction.

Analysis of Passive Earth Pressure and Displacements of Retaining Walls Using Pseudo-Dynamic Approach

2010 ◽  
Vol 1 (1) ◽  
pp. 88-109
Author(s):  
B. Munwar Basha ◽  
G. L. Sivakumar
Keyword(s):  
Dynamic Method ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Passive Earth Pressure ◽  
Planar Mechanisms ◽  
Composite Failure ◽  
Earth Pressures ◽  
Planar Failure ◽  
Seismic Accelerations ◽  
The Comparative Study

Using additional dynamic parameters in the pseudo-static method like shear wave and primary wave velocities of soil, phase change in the shear and primary waves, and soil amplification for seismic accelerations, one can benefit from another useful tool called pseudo-dynamic method to solve the problem of earth pressures. In this study, the pseudo-dynamic method is used to compute the seismic passive earth pressures on a rigid gravity retaining wall by considering both the planar failure and composite failure (log-spiral and planar) mechanisms. To validate the present formulation, passive earth pressure computed by the present method are compared with those given by other authors. Seismic passive earth pressure coefficients are provided in tabular form for different parameters. The sliding and rotational displacements are also computed and results of the comparative study showed that the assumption of planar failure mechanism for rough soil-wall interfaces significantly overestimates passive earth pressure and underestimate the sliding and rotational displacements.

Analytic solutions of rupture angle in coulomb's earth pressure theory

2013 ◽  
Vol 10 (6) ◽  
pp. 573-576
Author(s):  
Zhiguang Guo ◽  
Guoyong Cheng ◽  
Fan Wang
Keyword(s):  
Limit Equilibrium ◽  
Retaining Wall ◽  
Numerical Test ◽  
Engineering Application ◽  
Earth Pressure ◽  
Reference Value ◽  
Failure Surface ◽  
Analytic Solutions ◽  
Foundation Pit ◽  
Simplified Solution

Coulomb's earth pressure theory is widely used in foundation pit supporting structure and retaining wall design, and Rupture angle is one of the key parameters in determining the failure surface location and the foundation pit influence scope. But there is no explicit formula of rupture angle or some wrong in existing formula. This paper, according to the limit equilibrium condition of slide wedge, obtained the analytical expression of Rupture angle which is the most simplified form in the current information. Through the numerical test this simplified solution is consistent with coulomb theory. The conclusion of this paper has some reference value in engineering application of coulomb theory.

scholarly journals Calculation of Active Earth Pressure for Narrow Backfill with a Curved Slip Surface

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Zhihui Wang ◽  
Aixiang Wu ◽  
Yiming Wang
Keyword(s):  
Equilibrium Equation ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Failure Surface ◽  
Friction Angle ◽  
Force Balance ◽  
Vertical Force ◽  
The Earth

A method was proposed to calculate the earth pressure from a cohesionless backfill with a high aspect ratio (ratio of height to width of retaining wall). An exponential equation of slip surface was proposed first. The proposed nonlinear slip surface equation can be obtained once the width and height of the backfill as well as the internal friction angle of the backfill were given. The failure surface from the proposed formula agreed well with the experimental slip surface. Then, the earth pressure was calculated using a simplified equilibrium equation based on the proposed slip surface. It is assumed that the minor principal stress of the backfill near the wall and at its corresponding slip surface where the depth is the same is the same. Thus, based on the vertical force balance of the horizontal backfill strip, assuming the wall-soil interface and the slip surface is in the limit equilibrium state, defined by the Mohr–Coulomb criterion, the differential equilibrium equation was obtained and numerically solved. The calculated results agreed well with the test data from the published literature.

scholarly journals Pipe–soil interaction model for current-induced pipeline instability on a sloping sandy seabed

2016 ◽  
Vol 53 (11) ◽  
pp. 1822-1830 ◽  
Author(s):  
Fu-Ping Gao ◽  
Ning Wang ◽  
Jinhui Li ◽  
Xi-Ting Han
Keyword(s):  
Limit Equilibrium ◽  
Slope Angle ◽  
Interaction Model ◽  
Earth Pressure ◽  
Model Verification ◽  
Soil Resistance ◽  
Passive Earth Pressure ◽  
Equilibrium Approach ◽  
Full Scale Tests ◽  
Good Agreement

As offshore exploitation moves to deeper waters, ocean currents become the prevailing hydrodynamic loads on pipelines, and at the same time a sloping seabed is always encountered. The prediction of lateral soil resistance is vital in evaluating pipeline on-bottom stability. Unlike previous pipe–soil interaction models used mainly for horizontal seabed conditions, a pipe–soil interaction model for current-induced downslope and upslope instabilities is proposed by using the limit equilibrium approach. The Coulomb’s theory of passive earth pressure for the sloping seabed is incorporated in the derivation. The model verification with existing full-scale tests shows good agreement between the experimental results and predicted ones. Parametric study indicates that the effect of slope angle on pipeline lateral soil resistance is significant in the examined range of slope angle from –15° to 15°. The critical pipeline embedment and corresponding passive pressure decrease approximately linearly with increasing slope angle.

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