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为了判断武广客运专线浏阳河隧道DIIK1563+340～DIIK1563+410地段上台阶开挖时围岩的横向稳定性,应用强度折减法原理和有限元仿真软件建立每个强度折减系数下的仿真模型,研究拱顶沉降、地表沉降、主应力和塑性区与强度折减系数的关系,并分析隧道失稳形态。结果显示隧道的稳定安全系数为2.3,破坏首先发生在隧道两侧拱脚附近,然后向拱腰发展,并向地表扩展;拱顶沉降、地表沉降、塑性区对强度折减系数较敏感。因此,隧道施工中应保证锁脚锚杆的安设质量及工字钢落脚的稳固;并考虑监测中变形容易监测而塑性区不易监测,隧道监测应以拱顶沉降或地表沉降作为隧道失稳的主要判据。
In order to determine the lateral stability of surrounding rock during the step excavation of DIIK1563 + 340 ~ DIIK1563 + 410 on Liuyanghe Tunnel of Wuhan-Guangzhou Passenger Dedicated Line, the strength reduction method and finite element simulation software were used to establish the simulation model under each strength reduction coefficient The relationship between vault settlement, surface subsidence, principal stress, plastic zone and strength reduction factor was studied. The instability of the tunnel was analyzed. The results show that the safety factor of the tunnel is 2.3. The failure firstly occurs near the arch on both sides of the tunnel, then develops toward the arch and extends to the surface. The vault settlement, surface settlement and plastic zone are more sensitive to the strength reduction coefficient. Therefore, the construction of the anchor bolt should be ensured and the stability of the I-beam should be ensured during the tunnel construction. Considering the deformation in the monitoring is easy to monitor and the plastic zone is not easy to monitor. Tunnel monitoring should be based on vault settlement or surface subsidence as the tunnel instability The main criterion.