Breakage Probability Calculation of Shield Tunnel under the Effect of Foundation Pit Excavation

The excavation of foundation pit will change the initial stress state in surrounding soils, which induce the superimposed stress and uneven settlement to the adjacent existing tunnels. Based on the pit excavation engineering in Shenyang, which sits atop the existing tunnels, the risk factors and failure type of shield segment lining were studied through risk analysis theory. According to the uncertainty and spatial variability of soil parameters, the risk accident of existing tunnel was calculated by means of stochastic finite element which is combined Monte Carlo simulation with FEM. The risk of existing tunnel during the pit excavation stage was evaluated respectively under multi-failure patterns. The framework is used to estimate and minimize risks at pit excavation engineering in Shenyang.