浅埋铁路隧道下穿高速公路施工方案研究

Study on the Construction Scheme of Shallow Buried Railway Tunnel Underpassing Expressway

本文以新建兰渝铁路熊洞湾隧道为工程背景,针对工程环境复杂、对高速公路影响大、风险高等施工难点,开展了弧形导坑和台阶法施工工法比选。采用ANSYS有限元软件分别模拟浅埋铁路隧道下穿高速公路两种不同工序的施工过程,重点研究开挖过程高速公路路面变形和沉降槽宽度、隧道围岩塑性区分布以及衬砌结构受力。分析得出隧道开挖过程高速公路路面变形和沉降槽宽度,隧道周边岩体的塑性区域分布,以及隧道衬砌结构受力,确定了弧形导坑施工工法更加适合该隧道施工。根据数值分析结果,设计中采用了弧形导坑法工法、大管棚、型钢钢架、地表变形监控、控制爆破等手段,确保隧道施工安全。

Taking Xiongdongwan tunnel of Lan Yu railway as background,for the complex engineering environment,impact on the highway and high risk construction difficulties,two kinds of construction methods,arc heading and bench method of are selected. Two different construction excavation are simulated by using ANSYS finite element software,focusing research on the highway pavement deformation,settlement trough width,the stress characteristic of tunnel lining and the plastic areal distribution of surrounding rock. The result of contrastive analysis indicates that arch heading method is more suitable for this tunnel. In order to ensure the safety of tunnel construction,the arc heading method,big pipe shed and steel frame,the surface deformation monitoring and control blasting method are applied in the design.