A particle mechanics approach for the dynamic strength model of the jointed rock mass considering the joint orientation |
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| Authors: | Changtai Zhou Chaoshui Xu Murat Karakus Jiayi Shen |
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| Institution: | 1. Institute of Deep Earth Sciences and Green Energy, Shenzhen University, Shenzhen, China;2. School of Civil, Environmental and Mining Engineering, The University of Adelaide, Adelaide, Australia;3. Institute of Port, Coastal and Offshore Engineering, Zhejiang University, Hangzhou, China |
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| Abstract: | In nature, there exist several forms of anisotropy in rock masses due to the presence of bedding planes, joints, and weak layers. It is well understood that the anisotropic properties of jointed rock masses significantly affect the stability of surface and underground excavations. However, these critical anisotropic characteristics are often ignored in existing uniaxial dynamic failure criteria. This study investigates the effect of a pre-existing persistent joint on the rate-dependent mechanical behaviours of a rock mass using a particle mechanics approach, namely, bonded particle model (BPM), to realistically replicate the mechanical response of the rock mass. Firstly, in order to capture the rate-dependent response of the jointed rock mass, the BPM model is validated using published experimental data. Then, a dynamic strength model is proposed based on the Jaeger criterion and simulation results. To further investigate the dynamic behaviours, the dynamic uniaxial compressive strength (UCS) for anisotropic rock masses with various joint orientations is investigated by subjecting the BPM models to uniaxial compression numerical tests with various strain rate. The proposed dynamic strength model is validated based on numerical simulation results. Finally, the fragmentation characteristics of the jointed rock masses are analysed, which demonstrate that the failure mode affects the dynamic UCS. This is further confirmed by the analysis of the orientations of microscopic cracks generated by the compression loading. |
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| Keywords: | anisotropy bonded particle model Jaeger criterion loading rate uniaxial compression |
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