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| Failure mechanism of tailrace surge chamber in Jinchuan Hydropower Station based on microseismic monitoring and DFN simulation |
| PI Jintian1, XU Nuwen1*, ZHANG Fengshou2, MAO Haoyu1, ZHOU Xiang1,3, LI Huailiang4, BO Wu5
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1. State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, Sichuan, China;
2. Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai 200092, China;
3. Guodian Dadu River Basin Hydropower Development Co., Ltd., Chengdu 610041, Sichuan, China;
4. State Key Laboratory of Geohazard and Prevention and Geoenvirenment Protection, Chengdu University of Technology, Chengdu 610059, Sichuan, China;
5. School of Engineering, Tibet University, Lasa 850000, Xizang, China |
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Abstract In order to obtain the failure mechanism of the rock stability under the influence of carbonaceous phyllite band in tailrace surge chamber of Jinchuan Hydropower Station, an insitu microseismic(MS)monitoring system was established. In the construction period, the temporal and spatial distribution of MS events and source parameters were acquired during the excavation in underground caverns. A 3D discrete element numerical model was built. Discrete fracture network(DFN)was added for the weak fault of the underground caverns to build joint fissure, and the displacement and plastic zone distribution were obtained. The synthetic MS events induced by the excavation validated the failure mode and damage of the weak fault. The results suggested that there was a strong correlation between the spatial distribution of insitu MS events and the failure region of rock. The source parameter energy ratio of transverse and longitudinal waves of MS events revealed that the main failure mode of tailrace surge chamber was tension failure. The maximum deformation and plastic zone were obtained by discrete element numerical simulation, and the result was mutually verified with the MS monitoring results. The synthetic MS events generated by DFN-discrete element coupling method revealed the potential failure area of rock, and the result was in good agreement with the actual spatial distribution of MS events.
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Published: 20 September 2024
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