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| Effects of stress path on true triaxial macro and micro deformation characteristics of sandstone |
| WANG Zhechao1, ZHOU Erkang1,2
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1. Key Laboratory of Liaoning Province on Deep Engineering and Intelligent Technology, Northeastern University, Shenyang 110004, Liaoning, China;
2. State Key Laboratory of Hydraulic Engineering Simulation and Safety, School of Civil Engineering, Tianjin University, Tianjin 300350, China |
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Abstract In order to study the influence of stress path on the true triaxial macroscopic and mesoscopic deformation characteristics of rocks, a calibrated granular flow numerical specimen was established using the discrete element method, and the loading planes were selected as meridian plane, <i>π</i>-plane and the fixed-axis plane. Numerical experiments with different stress paths were conducted on the numerical specimen to analyze the true triaxial deformation evolution of rocks from the macroscopic and mesoscopic viewpoints, and the numerical simulation results were compared with the D-P yield criterion to verify the correctness of the results. The research results showed that:for the same stress increment, the anisotropy of strain increment was the lowest when loading along the meridian plane, and the stress reached the yield plane fastest when loading along the <i>π</i>-plane, resulting in the largest strain increment and the two-way unloading in fixed-axis plane produced the largest strain increment in all stress path loading processes. The elastic-plastic deformation characteristics were analyzed using the relative imaging of stress space and yield surface, defining deformation anisotropy parameters; the correlation between stress and strain increment paths was quantitatively analyzed at the mesoscopic view level, and it was concluded that the number of contact force chain transformations and strain increment deflection angle were negatively correlated, and the numerical model produced the largest number of microcracks with the most obvious internal damage when loaded along the <i>π</i>-plane, and the smallest number of microcracks with the least internal damage when loaded along the fixed-axis plane.
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Received: 16 February 2022
Published: 20 June 2022
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