Damage analysis and deformation early warning of surrounding rock mass during top arch excavation of underground powerhouse of#br# Shuangjiangkou hydropower station
(1. State Key Laboratory of Hydraulics and Mountain River Engineering，Sichuan University，Chengdu，Sichuan 610065，China；
2. Guodian Dadu River Basin Hydropower Development Co.，Ltd.，Chengdu，Sichuan 610041，China；3. No.1 Engineering Co.，Ltd.，China Gezhouba Group，Yichang，Hubei 443002，China)
Abstract：A three-dimensional spatial microseismic monitoring system of the underground powerhouse at the left bank of Shuangjiangkou hydropower station was constructed to pick up the surrounding rock microseismic signals during the excavation period，and the surrounding rock damage area was determined according to the microseismic activity characteristics. The relationship between spatio-temporal evolution characteristics and construction dynamic response of microseismic activity was analyzed based on conventional monitoring results and on-site exploration，and the evolution law of the fractal dimension of the surrounding rock from progressive damage to macroscopical deformation was revealed adopting the fractal-rock mechanics theory. The results show that the microseismic activity is closely related to the construction conditions and geological conditions. The microseismic event of the downstream side of 0–57 m–0–43 m in the installation interval is controlled by the blasting excavation strength and the giant rock mass fissure. The damage of surrounding rock mass exhibits non-shear rupture characteristics，and the microseismic signal shows low-frequency characteristics when the rupture scale increases. It is also revealed that the steep drop of the fractal dimension is the precursor signal of macroscopical deformation of surrounding rock mass. The research results can provide reference for the analysis of surrounding rock damage and deformation warning in underground powerhouse excavation.
钱 波1，徐奴文1，肖培伟1，2，赵铁栓3，董林鹭1. 双江口水电站地下厂房顶拱开挖围岩损伤分析及变形预警研究[J]. 岩石力学与工程学报, 2019, 38(12): 2512-2524.
QIAN Bo1，XU Nuwen1，XIAO Peiwei1，2，ZHAO Tieshuan3，DONG Linlu1. Damage analysis and deformation early warning of surrounding rock mass during top arch excavation of underground powerhouse of#br# Shuangjiangkou hydropower station. , 2019, 38(12): 2512-2524.
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2019, Vol. 38 
