不同地应力条件下巷道围岩松动圈演化研究

Study on Evolution of Loosing Rock Zone of Tunnel Surface under Different Ground Stress Conditions

基于Mohr-Coulomb准则,建立考虑不同侧压系数条件下的巷道围岩松动圈理论计算模型,结合工程算例对不同侧压系数的地应力条件下圆形巷道围岩松动圈范围进行了求解分析;采用数值模拟方法对巷道开挖的松动圈范围进行了计算,并与理论求解结果进行了对比分析。结果表明:①当侧压力系数λ=1时巷道围岩的塑性松动圈为圆形,且松动圈半径随地应力的增大而增大。②不同侧压力系数条件下巷道松动圈范围有所变化。顶底板围岩松动范围随λ的增大而增大。而当λ<1.0时巷道两侧壁松动范围随λ增大而减小,λ>1.0时随λ增大呈增大趋势,但整体上的变化量不大。③通过理论计算与数值模拟得出的松动圈分布规律基本一致。

Based on Mohr-coulomb criterion, a theoretical computation model about loosing rock zone of tunnel surrounding rocks under different lateral pressure coefficients was set up. Combined with a practical project, the range of loosing rock zone of circular roadway surrounding rocks under different lateral pressure coefficients is solved and analyzed. And the range of loosing rock zone during excavation is calculated by adopting the numerical simulation method, and the result are compared with that of the theoretical computation. The results showed that First, the loosing rock zone of tunnel surface is circle while lateral pressure coefficient λ= 1 and the radius of the loosing zone increase with ground stress increasing. Second, the range of loosing rock will vary with different lateral pressure coefficients. The loosing range of roof and floor surrounding rocks increase with λ increasing. But, the loosing range in side walls will decrease with A increasing while λ 〈 1. 0, and increase with λ increasing while λ 〉 1. 0. Last, the distribution law of loosing rock zone by theoretical calculating is basically identical to that by the numerical simulation.