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| Meso-fracture mechanism of granite specimens under high temperature and confining pressure by numerical simulation |
| TIAN Wenling1，2，YANG Shengqi1，2，HUANG Yanhua1，2，YIN Pengfei1，2，ZHU Zhennan1，2，SUN Bowen1，2 |
| (1. State Key Laboratory for Geomechanics and Deep Underground Engineering，China University of Mining and Technology，Xuzhou，Jiangsu 221116，China；2. School of Mechanics and Civil Engineering，China University of Mining
and Technology，Xuzhou，Jiangsu 221116，China) |
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Abstract To explore the mesoscopic fracture mechanism of granite under high temperature and confining pressure，GBM in PFC was adopted to simulate the triaxial tests of granite specimens after thermal treatment，and then the strain-strain curve，strength，failure modes and the fracture process were investigated. Based on the above analysis，the following conclusions can be obtained：GBM can reflect the interlock between grains and the nonlinear variation characteristic of the peak strength with confining pressure，and it also can overcome the problem that the circular particles is insufficient locking force. The peak strength of granite under different confining pressures is almost constant first and then decreases rapidly with increasing temperature，and 450 ℃ is the threshold temperature. The internal friction angle and cohesion first increase and then decrease with temperature，and the variation of the mechanical parameters is closely related to the mechanical structure of granite. After quartz underwent ?-? phase transition(573 ℃)，a large number of intra-granular cracks and inter-granular cracks occur in granite specimen. Under uniaxial compression，the fracture process of the specimen is controlled by thermal cracks，and the specimen exhibits ductile failure after the peak strength. Under high confining pressure，the shear band passes through the grain，loading to the brittle failure after the peak strength.
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2022, Vol. 41 
