Comprehensive Influence Analysis of Multiple Parameters on the Safety Thickness against Water Inrush in Shield Tunnel

This paper focuses on the construction of urban rail transit projects to prevent the risk of water inrush disasters faced during subway construction in cities with abundant groundwater and well-developed karst landforms. In view of the reserved safety thickness for the tunnel face with an anterosuperior karst cave filled with water in urban subway construction, the authors study the influence law and response sensitivity of different types and diameters of the shield machine cutter head and different diameters and water pressure of the anterosuperior karst cave filled with water on the safety thickness. The authors relied on the actual working conditions of the Wangfuzhuang station to the Dayangzhuang station section of the Jinan Metro Line R1 phase I project for this study used the fluid-structure coupling method of COMSOL Multiphysics 5.3 software to simulate the process of shield tunneling and the time of water inrush, and combined the three-dimensional finite-element numerical simulation results and multiple linear regression method to deduce the formula of the reserved safety thickness for the tunnel face with an anterosuperior karst cave filled with water. The conclusions can be used to guide shield excavation in karst areas of urban subways.