Effective stress in soils under different saturation conditions

作     者：徐浩峰 谢康和 

作者机构：Key Laboratory of Soft Soils and Geoenvironmental Engineering of Ministry of Education Zhejiang University Ningbo Institute of Technology Zhejiang University 

出 版 物：《Journal of Central South University》 (中南大学学报（英文版）)

年 卷 期：2011年第18卷第6期

页      面：2137-2142页

核心收录：

学科分类：08[工学] 080104[工学-工程力学] 0815[工学-水利工程] 0801[工学-力学（可授工学、理学学位）] 

基　　金：Project(50878191) supported by the National Natural Science Foundation of China Project(Y12E090030) supported by Zhejiang Provincial Natural Science Foundation, China 

主　　题：unsaturated soils effective stress suction surface tension occluded gas saturation 

摘      要：BISHOP’s effective stress or two state stress variables are unsatisfactory for unsaturated soils where one of fluid phases is discontinuous, so new expressions of effective stress should be founded. The approach for derivation was according to the principle of equilibrium of forces (i.e., the stress-sharing principle), and it was firstly validated by demonstrating TERZAGHI’s principle of effective stress. And then, the derivations were subdivided into four parts according to different pore air states: 1) air bubbles were spherical and suspended in pore water; 2) air bubbles were bound on soil skeleton; 3) air bubbles held almost the single section of pore; 4) air phase was continuous. The different formulae of effective stress were presented. Conclusions are drawn as follows: 1) For nearly-saturated soils, the real effective stress would be a little smaller than TERZAGHI’s effective stress; 2) For soils in which air phase is discontinuous in the form of bubbles, a new concept of pore air elastic pressure is put forward, and the total stress can be constituted by effective stress, pore water pressure and pore air elastic pressure; 3) For soils in which air phase is continuous, effective stress is equal to the value of the total stress plus suction; 4) Suction can be divided into two parts: one is the effect caused by additional pressure, and the other is the contract action by the skin.