断层位置及强度对地下洞室围岩稳定性影响

Analysis on Influence of Fault Location and Strength on Deformation and Stress Distribution of Surrounding Rocks of Large Underground Openings

岩体工程的稳定性主要受岩体结构控制,而断层是岩体工程中最常见的一类规模较大的地质不连续面。断层的力学性质及其与洞室的相对位置关系决定了围岩的稳定状态,通过数值计算及三峡工程地下厂房变形监测分析表明:断层的存在严重恶化了围岩的应力及变形分布,不同断层位置、不同自然应力场条件下围岩的应力及变形特征存在着明显的差异;断层摩擦强度对断层位于顶拱部位时的围岩变形影响较大,而粘聚力对断层位于边墙部位时影响较大,而且这种影响规律随侧压系数的增大而增大。

The stability of rock mass project is mainly controlled by the rock mass structure, and faults are the large geological discontinuity plane commonly encountered in rock mass engineering. The stability of surrounding rocks is restricted by mechanical property and location to underground cavern of faults, the detailed studies carried out by analysis of numerical calculation and construction monitoring datum of underground powerhouse of Three Gorges Project show： the distribution of stress and deformation of surrounding rock masses containing a fault are badly deteriorated, the distribution of stress and deformation are obviously different under different natural stress field and position of fault; The influence of friction strength of fault on deformation of surrounding rocks is more obvious when a fault is located near the crown, but the cohesion is more when wall nearby, and the influence is more distinct with side pressure coefficient increases.