深回填土区隧道群预留核心土法开挖数值模拟研究

Numerical Simulation of Tunnel Group Excavation with Reserved Core Soil Method in Deep Backfill Area

文章以重庆轨道交通十号线二期工程兰花路站为背景,开展深回填土区暗挖隧道群力学特性的数值模拟研究。依据工程场地地勘资料及隧道支护结构设计,建立三维有限元Midas-GTS NX模型。从围岩变形、应力特征及塑性分布特征三个方面,对隧道群预留核心土法开挖围岩应力应变特征随施工步序影响研究。研究表明,深回填土区预留核心土法开挖隧道围岩的位移、应力以及塑性区范围均可以满足稳定和安全要求,其中隧道群拱顶与拱底区域有明显较大范围的压应力区,在隧道施工过程中应尽快施作二衬,形成支护闭环。

Based on the background of Lanhua Road Station of Chongqing Rail Transit Line 10 phase II project, this paper carries out the numerical simulation research on the mechanical properties of tunnel group in deep backfill area. From three aspects of surrounding rock deformation, stress characteristics and plastic distribution characteristics, this paper studies the influence of construction sequence on the stress-strain characteristics of surrounding rock in tunnel group excavation with reserved core soil method. The results show that the displacement, stress and plastic zone of the surrounding rock of the tunnel excavated by the reserved core soil method in the deep backfill area can meet the requirements of stability and safety, and there is a large range of compressive stress zone in the vault and arch bottom of the tunnel group, so the secondary lining should be constructed as soon as possible to form a closed support loop.