高地应力深立井井筒围岩应力演化与变形规律及支护分析

Evolution-deformation law and support of surrounding rock in deep vertical shaft under high ground stress

深立井井筒开挖至深部后,所处的地质力学环境比浅埋更加复杂。为研究深部复杂应力环境下水平主应力对井筒围岩应力演化和变形规律的影响,采用理论分析和数值模拟的方法分析在不同侧压系数λ与水平应力比值k条件下,不同轴比(b/a)的井筒断面形状下井筒围岩应力演化和变形规律。结果表明:深立井井筒围岩的等应力轴比不同于深埋椭圆巷道的等应力轴比,深立井井筒围岩的等应力轴比与水平主应力的比值k有关;当侧压力系数与水平应力比值为定值时,不同井筒截面轴比时应力集中区主要分布在井筒x轴两端,变形较大处为y轴两端;从应力分布和变形角度分析,相同条件下井筒采用圆形断面开挖时围岩扰动效应最小;在分析井筒围岩应力与变形特征的基础上,提出井筒围岩双壳复合支护理念,并分析其加固机理。

With further excavation of deep vertical shaft, the geological and mechanical conditions become more complicated compared with shallow roadway. The horizontal crustal stress is the main reason for surrounding rock deformation and failure. Under different side pressure coefficient and horizontal stress ratio k,the section shape of vertical shafts with different axial ratio（ b / a） is selected to research the stress distribution and deformation features of surrounding rock. The result shows that the equal stress axial ratio of deep vertical shaft surrounding rocks is different from that of deep buried elliptic roadway. The equal stress axial ratio of deep vertical shaft surrounding rocks is related to the horizontal stress ratio k. When side pressure coefficient and horizontal stress ratio are both constant,stress concentration areas of different shaft cross-section axial ratio mainly distribute in both ends of the x-axis of the shaft. The maximum deformation is in both ends of the y-axis. From the stress distribution and deformation analysis,under the same conditions,when using circular section to excavate the shaft,the disturbance of the surrounding rock affects the minimum. Based on the analysis of shaft wall rock stress and deformation characteristics,the concept of shaft surrounding rocks double shell compound support is proposed,and its reinforcement mechanism is analyzed.