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Elastoplastic Anisotropic Damage Model of Carbonaceous Shale in Thermodynamic Framework
(1. State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038; 2. Yunnan Dianzhong Water Diversion Engineering Co., Ltd, Kunming 650000; 3 School of Civil Engineering, Central South University, Changsha 410075)
Abstract Carbonaceous shale is a kind of brittle rock encountered in the construction of tunnel engineering, which has typical nonlinear anisotropy characteristics. It is significantly important to established suitable constitutive model to approach the complicated mechanical behavior of this kind of rock. In this paper, an elastoplastic anisotropic damage constitutive model was proposed within the framework of thermodynamic. The plastic hardening/softening response is described by an improved Mohr-Coulomb yield criterion and the plastic flow is controlled by a non-associated flow rule. An exponential function form of damage criterion accounting for the anisotropic damage evolution was adopted to describe the degradation of stiffness. Plastic deformation and anisotropic damage evolution were coupled through combing“two surfaces”plastic yield criterion and damage criterion. Conventional triaxial compression tests were conducted on carbonaceous shale to exam the efficiency of the model. The comparison between the predictive result and experimental data suggests that the proposed model is capable to reproduce the damage evolution at different stress conditions and non-linearly mechanical behavior under compression of carbonaceous shale. In addition,the coupling between plastic deformation and anisotropic damage evolution was well produced. The proposed model can be implemented into FEM/FDM software to provide the theoretical support for stability and safety analysis of tunnel surrounding rock.
Abstract：
Carbonaceous shale is a kind of brittle rock encountered in the construction of tunnel engineering, which has typical nonlinear anisotropy characteristics. It is significantly important to established suitable constitutive model to approach the complicated mechanical behavior of this kind of rock. In this paper, an elastoplastic anisotropic damage constitutive model was proposed within the framework of thermodynamic. The plastic hardening/softening response is described by an improved Mohr-Coulomb yield criterion and the plastic flow is controlled by a non-associated flow rule. An exponential function form of damage criterion accounting for the anisotropic damage evolution was adopted to describe the degradation of stiffness. Plastic deformation and anisotropic damage evolution were coupled through combing“two surfaces”plastic yield criterion and damage criterion. Conventional triaxial compression tests were conducted on carbonaceous shale to exam the efficiency of the model. The comparison between the predictive result and experimental data suggests that the proposed model is capable to reproduce the damage evolution at different stress conditions and non-linearly mechanical behavior under compression of carbonaceous shale. In addition,the coupling between plastic deformation and anisotropic damage evolution was well produced. The proposed model can be implemented into FEM/FDM software to provide the theoretical support for stability and safety analysis of tunnel surrounding rock.
ZHANG Qiang1 ZHENG Lifeng1 SONG Meng2 LI Mei2 JIA Chaojun3
.Elastoplastic Anisotropic Damage Model of Carbonaceous Shale in Thermodynamic Framework[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(5): 1-9
2022, Vol. 59 