考虑累积微震损伤效应的荒沟电站地下洞室群围岩稳定性分析

微震监测作为开挖岩体附加损伤的指示器,已被广泛应用于地下工程施工期的围岩损伤区识别、圈定及稳定性分析评价中。然而,如何利用丰富的微震信息来标定岩体动态损伤过程中的力学参数,是定量评估围岩损伤程度及稳定性的关键。依托首座采用微震法岩爆监测的抽水蓄能电站工程--荒沟抽水蓄能电站,首先分析了地下洞室群施工期的微震活动性及围岩损伤情况;其次,建立以微震视体积确定岩体损伤尺度并考虑累积损伤效应的岩体劣化模型;最后,编写FISH语言将微震数据嵌入数值模拟中,首次实现了考虑累积微震损伤效应的地下洞室群围岩稳定性分析。结果表明:考虑累积微震损伤效应的围岩稳定性分析方法,有效利用了反映外界施工扰动和地质构造等异常活化的微震信息,岩体损伤程度、应力场和塑性区等分析结果与微震监测结果具有很好的一致性,对支护方案的优化设计具有指导意义。

Stability analysis of surrounding rock mass of underground caverns at Huanggou hydropower station considering cumulative microseismic damage effect

Microseismic monitoring,as an indicator to determine the additional damage of rock mass,has been widely used in the identification,delineation and stability evaluation of surrounding damage areas during underground engineering construction. However,how to use the abundant microseismic information to calibrate the mechanical parameters of the rock mass is the key to quantitatively evaluate the damage degree and stability of surrounding rock. Taking Huanggou pumped storage power station as the research background,which is the first pumped storage power station to adopt microseismic monitoring for rockburst,microseismic activity and surrounding rock damage of underground caverns during construction are firstly analyzed. Secondly,a rock mass deterioration model using microseismic apparent volume to determine rock mass damage scale and considering cumulative damage effect is established. Finally,the FISH language is written to embed microseismic data into numerical simulation,and the stability analysis of surrounding rock of underground caverns considering cumulative microseismic damage effect is realized for the first time. The results show that the surrounding rock stability analysis method considering the cumulative microseismic damage effect makes effective use of microseismic information reflecting abnormal activation such as external construction disturbance and geological structure,and that the analysis results of rock damage degree,stress field and plastic zone are in good agreement with microseismic monitoring results. The research work has guiding significance for optimal design of support scheme.