圆形巷道围岩扰动区及其临界破坏深度的确定

Determination of disturbed region and critical failure depth of surrounding rock in circular roadway

地下工程开挖的扰动区和围岩的临界破坏深度是与稳定性分析和支护设计紧密相关的问题,应用塑性力学折线理论所得应力场新成果对圆形巷道的扰动区和围岩的临界破坏深度进行了研究。一般认为扰动区的大小是井巷或采场最大直线尺寸的3～5倍,但分析表明扰动区范围与外载的大小与作用形式、泊松比和埋深有关,有时会远远超出这个范围。在围岩临界破坏深度的确定中,导出了各向同性均质地层中圆形巷道的临界破坏深度公式,结果表明临界破坏深度与地层强度峰值的黏聚力、内摩擦角、容重和泊松比相关。研究成果可为圆形巷道的稳定性评价及支护设计提供依据。

Disturbed region from excavation of underground engineering and critical failure depth of surrounding rock are closely related to stability and support design. Based on the new stress field solu- tion from the broken line theory of plasticity, disturbed region and critical failure depth of circular roadway were studied. The size of disturbed region is generally thought to be 3-5 times as large as the maximum dimension of tunnel or stope. The analysis has shown that the scope of disturbed region is re- lated to value and form of load, Poisson＇s ratio and excavation depth of roadway, and sometimes it may be far beyond the scope. In determination of the critical failure depth of surrounding rock, a critical fail- ure depth formula of circular roadway was presented for isotropic and homogeneous strata, which shows that critical failure depth is relative to C and μ of strata strength peak, weight and Poisson＇s ratio of strata. The above results will be of great help to stability evaluation and support design of circular roadway.