锦屏一级水电站左岸抗力体基础处理洞室群围岩稳定性分析

Analysis on Stability of Surrounding Rock of Underground Chamber Group on Left Bank Resisting Rock of Jinping-I Hydropower

摘要:

通过对锦屏一级水电站左岸抗力体五层洞室岩体结构特征详细调查，采用水电围岩分类的方法对抗力体洞室进行围岩分类。分类结果表明：抗力体洞室围岩以Ⅲ2类围岩居多，占了50%左右，其次为Ⅳ类，占36%左右，Ⅲ1和Ⅴ类围岩所占比例较少。通过对洞室施工开挖失稳破坏现象的调查研究，分析了洞室失稳破坏的机制及破坏形式，认为围岩主要的破坏形式为弱面控制型的块体滑移塌落。对洞室监测资料的分析结果表明，在目前的支护条件下，总体监测未见异常，整体上基础处理洞室监测状态稳定。但F5、F42-9断层及煌斑岩脉等软弱部位应力及变形缓慢增加，需要加强监测。最后根据分析结果提出了建议。

Abstract:

By the detailed survey on the structure features of left bank resisting rock of Jinping-I hydropower, resisting rock chambers were classified with surrounding rock classification. 50% resisting rock chambers belong to Ⅲ2, about 36% belong to Ⅳ, and the rest belong to Ⅲ1 and Ⅴ. By the study on excavating destabilization, analysis was made on the stability-loosing mechanism and the deformation pattern. Weak-plane-controlling block gliding and collapsing were thought to be the main deformation pattern. According to the analysis on the chamber monitoring data, no evidence showed any abnormal; but deformation of F5, F42-9 faults and lamprophyre dyke were slowly occurred. The paper put forward the construction proposal.