On the Active Failure Surface in the Backfilled Clay behind Rigid Retaining Wall in Slope Engineering

2006 ◽  
Vol 306-308 ◽  
pp. 1497-1502
Author(s):  
X.C. Xu ◽  
Yu Yong Jiao
Keyword(s):  
Variational Principle ◽  
Analytic Solution ◽  
Retaining Wall ◽  
Field Tests ◽  
Earth Pressure ◽  
Failure Surface ◽  
Slope Engineering ◽  
Differential Element ◽  
Element Method

In the classical Coulomb’s earth pressure theory, the failure surface in the backfilled clay behind rigid retaining wall in slope engineering is assumed a plane. However, it has been proved by a number of laboratory and field tests that this failure surface is actually a curving surface. In this paper, based on the vertical differential element method and the variational principle, a new analytic solution to determine the actual failure surface in the backfilled clay is derived, and the effects of the backfilled clay’s properties as well as the effects of the retaining wall’s smoothness are discussed. The result obtained from the proposed approach is compared with Coulomb’s earth pressure theory.

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.

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.

The Heather Hill landslide: an example of a large scale toppling failure in a natural slope

1991 ◽  
Vol 28 (3) ◽  
pp. 410-422 ◽  
Author(s):  
M. A. Pritchard ◽  
K. W. Savigny
Keyword(s):  
British Columbia ◽  
Large Scale ◽  
Distinct Element ◽  
Failure Surface ◽  
Distinct Element Method ◽  
Slope Engineering ◽  
Columbia Mountains ◽  
Toppling Failure ◽  
Element Method

This paper is an inquiry into the suspected relationship between toppling and large deep-seated landslides along the Beaver Valley, Glacier National Park, British Columbia. The study area includes the Heather Hill landslide, one of several in the valley, and adjacent slopes that show varying degrees of toppling disturbance. The development of the Heather Hill landslide is simulated using the distinct element method of numerical analysis. The rock mass is modelled using deformable columns whose boundaries represent a coarse approximation of in situ discontinuity patterns. An intercalated change in the predominant lithologies and a concomitant change in discontinuity spacings are modelled by varying column thickness and material properties. The analysis confirms that a deep-seated failure surface can develop as a result of the toppling process. The intercalated change in lithologies and the related change in discontinuity spacings account for the curvilinear failure surface and the headscarp position of the Heather Hill landslide. These variables are believed to also control the overall distribution of landslides in the Beaver Valley. The paper demonstrates that the distinct element method provides an effective basis for quantitative analysis of large scale toppling. Many more applications will be needed to refine the geometric and material property generalizations used in this study. Nevertheless, the method appears to offer considerable promise for elucidating problems of rock slope behaviour in both slope engineering and geomorphology. Key words: toppling, landslide, British Columbia, mountains, numerical modelling, distinct element method.

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.

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.

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