Numerical simulation study on the multi-tunnel effect during excavation of the subway in Guanghua Road Station of Beijing metro line 10

In this paper,based on Guanghua Road Station geometric materials,the numerical simulation of the station under five different excavation orders was carried out by FLAC3D software.Through the comparisons of different excavation orders with the same support parameters and the same loading condition,the regularities of soil-stress,plastic region and displacement transformation about the station were put forward.After analyzing,the recommending excavating order of the multi-tunneling construction was proposed.The results showed:(1) the plastic regions mainly exist in the areas between different holes,and along the line which presents 45° from the vertical direction of the middle hole;(2) the horizontal expansion of the section of the middle hole plays an important role in the downward displacement of the ground surface,but to the multi-tunnel construction,excavating the left and right hole firstly can reduce the displacement effectively;(3) the arch structure of the main hole plays an very important role in reducing the downward displacement of the ground surface.