Numerical Simulation of Continuous Shield Tunneling based on a Dynamic Element-Deletion Technology

Abstract

Currently, the finite-element (FE) simulation of tunnel excavation usually adopts the birth-to-death approach, which directly removes the soil element in the excavation region. This approach simplifies the dynamic process of continuous excavation to a transient process, which ignores the time-dependent response of soils in front of the excavation face as well as the soil– cutterhead interaction. This study presents a novel FE method to simulate the dynamic and continuous shield-tunneling process. In this method, the state variables are calculated based on either the stress or strain tensor of any arbitrary elements in which the elements that extrude into the excavation chamber can be identified and eliminated using the element-deletion technology. Therefore, the dynamic and continuous excavation process of a shield machine can be accurately simulated. Furthermore, the method can be used to analyze the influence of the cutterhead geometrical parameters as well as its rotary and propulsion speeds on the stability of the excavation face. By analyzing the key construction parameters such as shield-tunneling speed, cutterhead speed, and slurry pressure, the superiority of the dynamic simulation is demonstrated.