Analysis of the Calculation Method of Active Earth Pressure of Unsaturated Expansive Soil

2012 ◽  
Vol 594-597 ◽  
pp. 180-185
Author(s):  
Jia Shan Zhang
Keyword(s):  
Calculation Method ◽  
Expansive Soil ◽  
Earth Pressure ◽  
Swelling Pressure ◽  
Active Earth Pressure ◽  
Calculation Formula ◽  
Retaining Structure ◽  
Derivation Process ◽  
Sliding Soil ◽  
Unsaturated Expansive Soil

The properties of unsaturated expansive soil were analyzed, and the shortcomings of present methods which are explored to calculate the active earth pressure of unsaturated expansive soil on the retaining structure were discussed. Based on Coulomb’s earth pressure theory, a calculation formula of active earth pressure of unsaturated expansive soil was proposed taking into account of the swelling pressure parameters according to the condition of static equilibrium of sliding soil. The formula has simple composition and derivation process, is convenient for application, and the example shows that this method is reasonable.

Active earth pressure in cohesive soils with an inclined ground surface

2000 ◽  
Vol 37 (1) ◽  
pp. 171-177 ◽  
Author(s):  
Nirmala Gnanapragasam
Keyword(s):  
Analytical Solution ◽  
Ground Surface ◽  
Earth Pressure ◽  
Failure Surface ◽  
Friction Angle ◽  
Active Earth Pressure ◽  
Overburden Pressure ◽  
Retaining Structure ◽  
Lateral Earth Pressure ◽  
Fixed Orientation

An analytical solution is developed to determine the active lateral earth pressure distribution on a retaining structure when it consists of a cohesive backfill (internal friction angle ϕ > 0, cohesion c > 0) with an inclined ground surface. The solution derived encompasses both Bell's equation (for cohesive or cohesionless backfill with a horizontal ground surface) and Rankine's solution (for cohesionless backfill with an inclined ground surface). The orientation of the failure surface is also determined. Results indicate that, unlike the soil-wall scenarios of Bell and Rankine where the failure planes are parallel with a fixed orientation independent of the overburden pressure, for sloping cohesive backfill (ϕ > 0, c > 0) the slope of the failure surface is a function of the overburden pressure and becomes shallower with depth, thus forming a curvilinear failure surface. The solution developed can also be used to check the sustainability of a slope. The analytical solution can be programmed conveniently in a computer.Key words: retaining structure, active earth pressure, cohesive backfill.

scholarly journals Active Earth Pressure of Limited C-φ Soil Based on Improved Soil Arching Effect

2020 ◽  
Vol 10 (9) ◽  
pp. 3243
Author(s):  
Meilin Liu ◽  
Xiangsheng Chen ◽  
Zhenzhong Hu ◽  
Shuya Liu
Keyword(s):  
Retaining Wall ◽  
Pressure Coefficient ◽  
Ground Surface ◽  
Side Wall ◽  
Earth Pressure ◽  
Active Earth Pressure ◽  
Soil Arching ◽  
Retaining Structure ◽  
Arching Effect ◽  
Soil Arching Effect

For c-φ soil formation (cohesive soil) of limited width with ground surface overload behind a deep retaining structure, a modified active earth pressure calculation model is established in this study. And three key issues are addressed through improved soil arching effect. First, the soil-wall interaction mechanism is determined by considering the soil arching effect. The slip surface of a limited soil is proved to be a double-fold line passing through the retaining wall toe and intersecting the side wall of the existing underground structure until it reaches the ground surface along the existing side wall. Second, the limited width boundary is explicated. And third, the variation in the active earth pressure from parameters of limited c-φ soil is determined. The lateral active earth pressure coefficient is nonlinear distributed based on the improved soil arching effect of the symmetric catenary curve. Furthermore, the active earth pressure distribution, the tension crack at the top of the retaining wall and the resultant force and its action point were obtained. By comparing with the existing analytical methods, such as the Rankine method, it demonstrates that the model proposed in this study is much closer to the measured and numerical results. Ignoring the influence of soil cohesion and the limited width will exponentially reduce the overall stability of the retaining structure and increase the risk of accidents.

Study on the Influence of Active Earth Pressure Caused by the Ditch behind Retaining Wall

2012 ◽  
Vol 204-208 ◽  
pp. 255-258
Author(s):  
Guang Qi Sheng ◽  
Ying Hui Chen ◽  
Fang Sun ◽  
Bo Wei ◽  
Yan Lian Pan
Keyword(s):  
Calculation Method ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Plane Boundary ◽  
Infinite Plane ◽  
Active Earth Pressure ◽  
Regular Pattern ◽  
Distributed Load ◽  
Uniformly Distributed Load

To study the influence of active earth pressure caused by the ditch after retaining wall, we will treat the ditch as unloading, and use the resolve of uniformly distributed load on half-infinite plane boundary to get the calculation method to get the influence of active earth pressure caused by the ditch after retaining wall. At last, from an example, we will get the picture of active earth pressure caused by the ditch after retaining wall, and analysis the regular pattern and characteristics.

FIELD STUDY OF THE DISTRIBUTION OF LATERAL SWELLING PRESSURE OF EXPANSIVE SOIL ON RETAINING STRUCTURE

2014 ◽  
Vol 42 (2) ◽  
pp. 289-302
Author(s):  
Omer Zakaria Mohamed ◽  
Yehia K. Taha ◽  
El-Sharif M.Abd El-Aziz
Keyword(s):  
Field Study ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Retaining Structure

Active earth pressure due to soil mass partially subjected to water seepage

2015 ◽  
Vol 52 (11) ◽  
pp. 1886-1891 ◽  
Author(s):  
Petrucio J. Santos ◽  
Pérsio L.A. Barros
Keyword(s):  
Limit Equilibrium ◽  
Numerical Procedure ◽  
Earth Pressure ◽  
Numerical Results ◽  
Equilibrium Analysis ◽  
Exit Point ◽  
Active Earth Pressure ◽  
Seepage Analysis ◽  
Water Seepage ◽  
Retaining Structure

A method for determination of the active earth pressure exerted by a cohesionless backfill, subjected to water seepage from a high water table, on a retaining structure is presented. The method comprises a numerical procedure based on the boundary element method (BEM) for the seepage analysis and a trial wedge method for the limit equilibrium analysis. The numerical results of the seepage analysis are presented as normalized charts that can be used in the trial wedge method without recourse to the BEM computer code. The main benefits of the proposed analysis are the simplicity of use and the small amount of data necessary. For the seepage analysis, only the phreatic line exit point height at the retaining structure face is required. Numerical results obtained for a proposed example of a retaining wall show the influence of the water seepage on the active earth pressure. The analysis method also can deal with cases of soil anisotropy with respect to the permeability.

scholarly journals Experimental Study on Swelling Behavior and Its Anisotropic Evaluation of Unsaturated Expansive Soil

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zhengnan Liu ◽  
Rui Zhang ◽  
Zhaojing Liu ◽  
Yuming Zhang
Keyword(s):  
Normal Stress ◽  
Stress Ratio ◽  
Expansive Soil ◽  
Vertical Direction ◽  
Swelling Pressure ◽  
Matric Suction ◽  
Swelling Behavior ◽  
Passive State ◽  
Retaining Structures ◽  
Unsaturated Expansive Soil

Evaluation of swelling behavior is important for designing structures in expansive soils areas, especially for highway that the swelling pressure generated upon pavement and retaining structures in both vertical and horizontal directions due to infiltration. In this study, modification was made on unsaturated consolidation oedometer to provide synchronized measurement of vertical swelling strain (VSS) and lateral pressure (LP) of expansive soil under constant net normal stress and controlled matric suction. Vertical swelling (VS) test and lateral swelling (LS) test were conducted to investigate the anisotropic swelling behavior. The influence of mean net stress and net stress ratio on VSS was investigated, and the anisotropic swelling behavior of unsaturated expansive soil was characterized using anisotropic swelling ratio. The results show that the VSS nonlinearly decreased as the mean net stress increased and increased as the net stress ratio increased. The expansive soil would rapidly enter the passive state due to lateral swelling pressure under relatively low surcharge, with major principal axis rotating from vertical direction to lateral direction, which advances the possibility of passive failure for light retaining structures. The anisotropic swelling behavior objectively exists and varies with matric suction and net normal stress, which should not be ignored for engineering application.

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