Simulation Analysis of Deformation and Stress Characteristics of Shallow Double-arch Tunnel

3D numerical simulation analysis of shallow double-arch tunnel is conducted with detailed and realistic model,and the calculation parameters are determined by principle of equivalence.The results show that:excavation affects deformation and stress re-distribution significantly;initial and temporary supporting structure can control deformation effectively;the influence is in the range of a third radius;the middle-wall deflects a small angle as a whole during construction and the compressive stress is large in middle-wall.