大跨度洞室开挖施工方案研究

Study on the excavation scheme of the large span tunnel

针对某工程隧洞进口闸室段开挖跨度大,上覆岩体薄,围岩为V类的具体情况,本文以减小开挖断面跨度以及新奥法施工方法的基本原理为出发点,对该隧洞进口闸室段的两种开挖方案进行了分析研究。用有限元方法得到了洞室外围岩的位移场、应力场分布。比较这两种方案,最终得出了在围岩稳定以及支护结构稳定情况下较为理想的开挖与支护方案。

Aiming at the large span, thin overburden on the entrance section of tunnel, based on the NATM theory and reducing of span, two excavation scheme have be studied. Displacement, stress in surrounding rockmass and supporting system have been gained by FEM. Comparing two excavation scheme, the optimized excavation scheme is suggested.