基于围岩-支护特征理论的高地应力软岩隧道初期支护选型研究

Research on selection of preliminary support for tunnel in high ground-stress soft rock based on surrounding rock-support characteristic curve theory

结合正在修建的兰新铁路第二双线LXS-7标的极高地应力大梁隧道,开展型钢钢架与格栅钢架支护机理研究。在综合考虑喷射混凝土时间硬化效应对初期支护强度的影响基础上,基于围岩-支护特征理论综合分析型钢钢架及格栅钢架的支护机理及其适应性,探索高地应力软岩隧道工程中不同刚度支护的力学响应过程,绘制高地应力软岩隧道几种可能的围岩-支护特征曲线,为高地应力软岩隧道合理支护形式的确定提供理论依据,并提出适合于围岩大变形的合理支护形式,以及控制高地应力软岩隧道大变形的合理措施。

According to the surrounding rock-support characteristic curve theory,the supporting mechanisms of shaped steel frame and steel grid frame in high ground-stress regions were discussed during the construction of Daliang tunnel in LXS-7 of Lanzhou-Xinjiang double-track railway. Different forms of tunnel supports with varied stiffness were applied to the tunnel, and their deformation mechanisms and mechanical responses were also investigated. Based on the surrounding rock-support characteristic curve theory,several possible rock-support characteristic curves,which may be used as theoretical evidences,were attained for the tunnels in high ground-stress soft rock. Furthermore,the support form suitable for large-deformation rock was proposed,and some adequate measures to control the large deformation of rock in high ground stress were suggested.