不同开挖方案下尾调室穹顶围岩稳定性分析

运用FLAC3D数值分析软件,对无支护条件下某水电站左岸#1尾调室在两种施工方案下穹顶的围岩稳定性进行分析,并对#1尾调室穹顶围岩的应力分布特征、变形特征、塑性区分布特征等计算结果进行比较和分析,从而说明了两种开挖方案下围岩可能会出现的破坏特征。计算结果表明:与开挖方案1相比,开挖方案2不存在第3步开挖后的顶拱的应力集中和边墙的应力松弛问题,同时不会加大穹顶变形稳定问题,推荐采用第2种方案。

Analysis on Stability of Rock Surrounding Dome of Tailrace Surge Chamber under Different Excavation Schemes

With the numerical analysis software of FLAC3D, the stability of rock surrounding the dome of the tailrace surge chamber #1 at the left bank of a hydropower station without any support was analyzed. The characteristics with regard to the stress distribution, deformation, plastic zone distribution of the rock surrounding the dome were calculated with the results compared and analyzed, elaborating the characteristics of rock failure likely developed. The calculation result shows that, compared with the scheme 1, the scheme 2 is free of stress concentration at the vault and stress relief at the side wall after the step 3 excavation; simultaneously, the dome deformation would not be increased. Therefore, the excavation scheme 2 is recommended.