基于Hoek-Brown强度准则的隧道围岩松动圈分析

摘要

分析松动圈的分布范围对优化隧道支护参数,确保隧道施工安全有重要的理论价值,以弹塑性理论计算为基础,利用H-B强度准则推导了理想状态下围岩松动圈厚度的计算公式.当侧压力系数不等于1时,将实测竖直方向和水平方向的初始地应力分别带入,并考虑实际支护力的影响,得到较为准确的围岩松动圈分布规律.在铜旬高速某公路隧道中该方法计算所得围岩松动圈分布范围与围岩深部位移监测所得结果较为接近,验证了基于H-B强度准则的围岩松动圈计算公式的准确性,为确定围岩松动圈半径提供了新的有效方法.%The disturbance produced during tunnel excavation process destroys the initial stress state of surrounding rock, causes stress redistribution and thus generates broken zone of surrounding rock.The analysis on the distribution range of broken zone is of important theoretical value for optimization of tunnel supporting parameters and ensuring the safety of tunnel construction.The formula for calculating the broken zone thickness of surrounding rock under ideal state was derived with Hoek|Brown(H|B) strength criterion on the basis of elastic|plastic theoretical calculation.The comparatively accurate distribution regularities of broken zone of surrounding rock were obtained by respectively substituting into the measured initial ground stress in the vertical and horizontal direction when the lateral pressure coefficient is not equal to 1, with considering the effect of actual support force.The calculated distribution range of broken zone of surrounding rock was comparatively close to the monitoring results of deep displacement in surrounding rock of a certain highway tunnel of Tongchuan|Xunyi expressway, which verified the accuracy of calculation formula on broken zone of surrounding rock based on H|B strength criterion.It provides a new effective method for determining the radius of broken zone of surrounding rock.