Mechanical response and stability analysis of surrounding rock mass during roof arch excavation of underground powerhouse under high in-situ stress
DONG Linlu1，2，LI Peng3，LI Yonghong4，ZHAO Tieshuan5，SUN Yuepeng1，2，XIAO Peiwei1，2，#br#
YANG Xingguo1，2，XU Nuwen1，2
(1. College of Water Resource and Hydropower，Sichuan University，Chengdu，Sichuan 610065，China；2. State Key Laboratory of Hydraulics and Mountain River Engineering，Sichuan University，Chengdu，Sichuan 610065，China；3. Guodian Dadu River Basin Hydropower Development Co.，Ltd.，Chengdu，Sichuan 610041，China；4. PowerChina Chengdu Engineering Corporation Limited，Chengdu，Sichuan 610072，China；5. China Gezhouba Group No.1 Engineering Co.，Ltd.，Yichang，Hubei 443002，China)
Abstract：The geological structure of underground powerhouse caverns of hydropower stations is complex and the ground stress is high. Deformation and failure of surrounding rock mass occur frequently during construction. In order to solve the failure of roof arch during excavation of high stress underground powerhouse of one power station, the damage evolution process of surrounding rock was analyzed. The microseismic(MS) monitoring technology was used to record the process of surrounding rock mass microfracture initiation and propagation during excavation of underground powerhouse in real time. The response laws of deep surrounding rock damage and construction dynamics were revealed through routine monitoring and site survey. The progressive evolution characteristics of stress field and displacement field during excavation were reproduced by numerical simulation. The research results show that the MS activity is closely related to the construction state and geological conditions. The MS events gathering in the K0–40–K0–60 area of the powerhouse are jointly controlled by strong unloading and joint fissures. The horizontal stress of the high side wall and the vertical stress of the top arch aggravate the damage evolution along the excavation axis. The focal parameters show that the moment magnitude increases，the apparent stress decreases，and the cumulative apparent volume remains unchanged before the deformation and failure of the surrounding rock mass. The research results can provide reference for the damage and stability evaluation of surrounding rock mass during excavation of similar underground engineering.
董林鹭1，2，李 鹏3，李永红4，赵铁拴5，孙悦鹏1，2，肖培伟1，2，杨兴国1，2，徐奴文1，2. 高应力地下厂房顶拱开挖过程围岩力学响应与稳定性分析[J]. 岩石力学与工程学报, 2023, 42(5): 1096-1109.
DONG Linlu1，2，LI Peng3，LI Yonghong4，ZHAO Tieshuan5，SUN Yuepeng1，2，XIAO Peiwei1，2，. Mechanical response and stability analysis of surrounding rock mass during roof arch excavation of underground powerhouse under high in-situ stress. , 2023, 42(5): 1096-1109.
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2023, Vol. 42 
