超大断面双侧壁导坑法核心土宽度研究

贵阳交通轨道2号线地铁车站观水路站地处贵阳老城区，人口众多、交通复杂、建筑密集。隧道围岩级别为ⅴ级，且属于超大断面隧道。为了减少隧道开挖引起的地层扰动。本文通过数值计算模拟了双侧壁导坑法开挖。分析了三种不同宽度的核心土对隧道开挖的稳定性影响。并综合分析了地表、拱顶、边墙以及拱底的位移与力学特征，得出最优核心土宽度为10 308mm，同时建议开挖核心土时要加强监测与做好加固措施。

Study on the width of Core Soil by Double-sidewall Guide Pit Method with Super Large Section

Guanshui Road Station of Guiyang Traffic Rail Line No. 2 Metro Station is located in the old city of Guiyang with a large population, complex traffic and dense buildings. The surrounding rock of the tunnel is of the grade of v and belongs to the super section tunnel. In order to reduce the formation disturbance caused by tunnel excavation this paper simulates the excavation with double-side-drift method by numerical calculation. The influence of core soil of different widths on the stability of tunnel excavation is analyzed. The displacement and mechanical characteristics of surface, vault, side wall and arch bottom are analyzed synthetically. It is concluded that the optimal core soil width is 10 308mm and it is suggested that monitoring and reinforcement measures should be strengthened during the excavation of core soil.