西南某水电站三维地应力场分布规律研究

Study on the distribution of in-situ stress field in a hydropower station in Southwest China

地应力对于分析水电工程的地下洞室或厂房稳定性至关重要,为分析西南某大型水电站的三维地应力场分布规律,保证地下厂房洞室群的稳定性,对水电站现场进行了实地地质调查,分析了所获取的大量地应力实测资料和探洞片帮特征,并对探洞片帮进行了数值模拟计算。研究结果表明:该水电站总体上水平向应力大于自重应力,以构造应力为主;右岸岩体地应力大于左岸岩体地应力,左、右岸厂房区及河谷区有应力松弛和应力集中,岸坡区有应力松弛现象;水电站左岸、河谷及右岸地应力方向存在明显差异,左岸厂房区的地应力方向为NW向,右岸厂房区地应力方向为NNE向,河谷为EW向,整个工程区地应力是以构造应力为主的中等量级地应力。研究结果为该水电站地下洞室稳定性分析提供了相关参考和依据。

In-situ stress is very important for stability analysis of underground caverns or powerhouses in hydropower projects.In order to analyze the three-dimensional in-situ stress distribution law of a large hydropower station in southwest China,the site geological survey is implemented.The characteristics of the rib spalling in tunnel and abundant in-situ stress data are analyzed,and the numerical simulation of rib spalling is carried out.The results show that the horizontal in-situ stress is larger than the gravity stress,and the tectonic stress is the control stress.The in-situ stress of rock mass in the right bank is larger than that in the left bank.and the phenomenon of stress relaxation and stress concentration are both exist in the workshop area and valley.The direction of in-situ stress in the left and right bank or the valley are obviously different.It is the NW direction in the workshop area in the left bank,and is NNE direction in the right bank and EW direction in the valley,respectively.The in-situ stress field in the whole area is dominated by a medium tectonic stress.The research results provide a reference and basis for the stability analysis of underground caverns of the hydropower station.