超大断面隧道不同开挖工法力学特征研究

STUDY ON MECHANICAL CHARACTERISTICS OF DIFFERENT EXCAVATION METHODS FOR SUPER LARGE SECTION TUNNELS

采用FLAC软件数值模拟的手段对超大断面隧道不同开挖工法力学特征进行研究,通过分析不同开挖方法及支护条件下围岩扰动效应以及不同开挖方法及支护条件下超大扁平公路隧道荷载演变特征,得出以下结论:CD法开挖部更多,能更好地控制围岩和结构变形,却承受了更大的围岩压力;中隔壁台阶开挖部更少,虽然能加快施工进度,却使得围岩产生更大的变形;而钢架岩墙组合支撑法兼顾二者,既能很好地控制变形,又能达到快速施工的效果。

By means of FLAC software numerical simulation, the mechanical characteristics of different excavation methods for super large section tunnels are studied. By analyzing the surrounding rock disturbance effect under different excavation methods and support conditions and the load evolution characteristics of super large flat highway tunnels under different excavation methods and support conditions, the following conclusions are drawn:CD method has more excavation parts, which can better control the deformation of surrounding rock and structure,but bears greater surrounding rock pressure. There are fewer benches in the middle wall, which can accelerate the construction progress, but cause greater deformation of the surrounding rock. The combined support method of steel frame rock wall can not only control the deformation, but also achieve the effect of rapid construction.