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

Abstract

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.

Analytical Solution for the Steady Seepage Field of a Foundation Pit in an Anisotropic Layer

“…However, this paper made simplifications and did not consider the thickness of the retaining wall. Precipitation is a common measure in foundation pit excavation, but the water level distribution around the pit after precipitation is curved and will not be a constant [27], which will introduce a lot of difficulties in the analytical solution. Therefore, the seepage field of the pit, considering the thickness of the retaining wall and the precipitation measures, can be further investigated in future studies based on the analytical solution presented in this paper.…”