Surface Settlement Analysis of Double-Line Shield Passing Through a Power Tunnel and Directly Cutting Pile Foundation

Abstract

Three-dimensional numerical simulation was conducted to investigate the influence of shield directly cutting the pile foundation of surface settlements using the Hangzhou Metro Line 4 shield passing through a power tunnel. The thrust force of the tunnel working face and grouting pressure are used as the tunneling parameters for the numerical simulation, from which field monitoring data is obtained and analyzed. The simulation results are verified to a certain extent by comparing them with the monitoring data. The power tunnel with high stiffness acts as a beam in the soil and can effectively reduce soil settlement, making the settlement curve affected by the power tunnel no longer axisymmetric. The final surface settlement value decreases with the increase of thrust force of the tunnel working faceand grouting pressure. In the influence range of the power tunnel, the thrust of the tunnel working face has a significant effect on the width of the settlement trough, while the effect of grouting pressure on the width of the settlement trough is not as significant as with the thrust.