Acta Mechanica Solida Sinica

, Volume 22, Issue 3, pp 251–260

# Theoretical model of effective stress coefficient for rock/soil-like porous materials

• Kai Zhang
• Hui Zhou
• Dawei Hu
• Yang Zhao
• Xiating Feng
Article

## Abstract

Physical mechanisms and influencing factors on the effective stress coefficient for rock/soil-like porous materials are investigated, based on which equivalent connectivity index is proposed. The equivalent connectivity index, relying on the meso-scale structure of porous material and the property of liquid, denotes the connectivity of pores in Representative Element Area (REA). If the conductivity of the porous material is anisotropic, the equivalent connectivity index is a second order tensor. Based on the basic theories of continuous mechanics and tensor analysis, relationship between area porosity and volumetric porosity of porous materials is deduced. Then a generalized expression, describing the relation between effective stress coefficient tensor and equivalent connectivity tensor of pores, is proposed, and the expression can be applied to isotropic media and also to anisotropic materials. Furthermore, evolution of porosity and equivalent connectivity index of the pore are studied in the strain space, and the method to determine the corresponding functions in expressions above is proposed using genetic algorithm and genetic programming. Two applications show that the results obtained by the method in this paper perfectly agree with the test data. This paper provides an important theoretical support to the coupled hydro-mechanical research.

## Key words

rock/soil-like porous materials generalized model for effective stress coefficient tensor equivalent connectivity index of pore genetic algorithm

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© The Chinese Society of Theoretical and Applied Mechanics and Technology 2009

## Authors and Affiliations

• Kai Zhang
• 1
• Hui Zhou
• 1
• Dawei Hu
• 1
• Yang Zhao
• 1
• Xiating Feng
• 1
1. 1.State Key Laboratory of Geomechanics and Geotechnical EngineeringInstitute of Rock and Soil Mechanics, Chinese Academy of SciencesWuhanChina