Discussion of ‘Study on the action of the active earth pressure by variational limit equilibrium method’ by Li Xinggao and Liu Weining, International Journal for Numerical and Analytical Methods in Geomechanics 2010; 34:991-1008

Calculation methods for active earth pressure of retaining wall are analyzed and discussed, and then based on energy conservation principle, one formula about calculation of active earth pressure was deduced which was illustrated with two engineering examples. The results suggest: compared with other limit equilibrium method, this method is closer to practical action and relatively simple, and is applicable to any case calculation for active earth pressure of wall retaining, so has high promotion value.

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

Canadian Geotechnical Journal ◽

10.1139/t99-123 ◽

2000 ◽

Vol 37 (2) ◽

pp. 485-491 ◽

Cited By ~ 23

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.

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Estimating critical height of unsupported trenches in vadose zone

Canadian Geotechnical Journal ◽

10.1139/cgj-2019-0069 ◽

2021 ◽

Vol 58 (1) ◽

pp. 66-82

Author(s):

Adin Richard ◽

Won Taek Oh ◽

Gregory Brennan

Keyword(s):

Finite Element ◽

Vadose Zone ◽

Pore Water Pressure ◽

Limit Equilibrium ◽

Water Pressure ◽

Earth Pressure ◽

Limit Equilibrium Method ◽

Critical Height ◽

Element Analysis ◽

Equilibrium Method

Workers are often required to enter unsupported trenches during the construction process, which may present serious risks. Trench failures can result in death or damage to adjacent properties; therefore, trenches should be excavated with extreme precaution. Critical height (i.e., maximum depth that can be excavated without failure) is the most important design consideration for ensuring the stability of unsupported trenches. Because excavation work is often done in the vadose zone, the influence of matric suction should be taken into account when estimating the critical height of an unsupported trench. In this study, an attempt was made to estimate the critical heights of unsupported trenches using three distinct approaches: (i) analytical method based on the extended Rankine earth pressure theory, (ii) finite element coupled stress – pore-water pressure analysis, and (iii) limit equilibrium method (i.e., Bishop’s simplified and Morgenstern–Price method). It was assumed that the trenches were excavated in an engineered sand (Unimin 7030) and Indian Head till, which represent cohesionless and cohesive soils, respectively, considering various practical scenarios. Geotechnical modeling software, GeoStudio (ver. 2016; SIGMA/W and SLOPE/W), was used for both finite element analysis and the limit equilibrium method.

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Limit Support Pressure of Tunnel Face in Multi-Layer Soils Below River Considering Water Pressure

Open Geosciences ◽

10.1515/geo-2018-0074 ◽

2018 ◽

Vol 10 (1) ◽

pp. 932-939 ◽

Cited By ~ 2

Author(s):

Weiping Liu ◽

Lina Hu ◽

Yongxuan Yang ◽

Mingfu Fu

Keyword(s):

Numerical Method ◽

Limit Equilibrium ◽

Water Pressure ◽

Earth Pressure ◽

Limit Equilibrium Method ◽

Support Pressure ◽

Tunnel Face ◽

Equilibrium Method ◽

Tunnel Design ◽

Design And Construction

AbstractThis paper presents a method to determine the limit support pressure of tunnel face in multi-layer soils below river considering the water pressure. The proposed method is based on the 3D Terzaghi earth pressure theory and the wedge theory considering the water pressure. The limit support pressures are investigated using the limit equilibrium method and compared to those calculated using a numerical method, such as FLAC3D. Four cases focusing different combinations of three layers are analyzed. The results obtained by the numerical method agree well with the predictions of the proposed limit equilibrium method. The limit support pressure obtained using the limit equilibrium method is greater than that obtained by the numerical method. The limit equilibrium method is safe and conservative in obtaining the limit support pressure. The proposed limit equilibrium method is expected to be easily adaptable and to enhance the reliability of tunnel design and construction in multi-layer soils below river.

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