A creep constitutive model for transversely isotropic rocks

Authors

Lie-lie LI, School of Civil Engineering and Communication, North China University of Water Resources and Electric Power, Zhengzhou, Henan 450045, China
Jun-feng GUAN, School of Civil Engineering and Communication, North China University of Water Resources and Electric Power, Zhengzhou, Henan 450045, ChinaFollow
Ming-li XIAO, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan 610065, China
Hai-chao LIU, School of Civil Engineering and Communication, North China University of Water Resources and Electric Power, Zhengzhou, Henan 450045, China
Ke-dong TANG, School of Civil Engineering and Communication, North China University of Water Resources and Electric Power, Zhengzhou, Henan 450045, China

Abstract

Due to the presence of bedded or jointed planes, layered rock mass shows transversely isotropic characteristics in mechanics. Therefore, the existing isotropic creep model is difficult to fully reflect the creep constitutive model of transversely isotropic rock mass. In order to obtain the three-dimensional transversely isotropic creep constitutive model, the Burgers model is adopted to describe the characteristics of instantaneous strain, decaying creep and steady creep of transversely isotropic rock mass. Based on the assumption of constant Poisson’s ratio and three-dimensional isotropic creep constitutive equation, a three-dimensional creep constitutive equation of transversely isotropic rock mass is derived through differential operator method by substitution of transversely isotropic compliance matrix into isotropic compliance matrix. The new model also takes the differences of creep behaviours between specimens with horizontally and vertically oriented bedding into account. According to the characteristics of creep constitutive equation, a method for identifying the creep parameters in the three-dimensional creep constitutive model is proposed based on the creep test results. The model is applied to the identification of triaxial creep test parameters, and a comprehensive set of three-dimensional creep parameters are obtained. The rationality of the proposed creep equation is verified by comparing theoretical values with experiment results. The limitations of the traditional creep tests design scheme are further pointed out and some suggestions for creep tests design of transversely isotropic materials are given. The research results provide a new insight for the study of three-dimensional creep mechanism of rock mass and provide scientific support for the design of rock mass creep tests.

Recommended Citation

LI, Lie-lie; GUAN, Jun-feng; XIAO, Ming-li; LIU, Hai-chao; and TANG, Ke-dong (2021) "A creep constitutive model for transversely isotropic rocks," Rock and Soil Mechanics: Vol. 41: Iss. 9, Article 4.
DOI: 10.16285/j.rsm.2019.6387
Available at: https://rocksoilmech.researchcommons.org/journal/vol41/iss9/4