Numerical Analysis of Ground Settlement Induced by a Double-O-Tube (Dot) Shield Tunnel Excavation

The soil mass is disturbed as the double-o-tube (DOT) shield tunnel boring machine advances, leading to ground displacements in all directions. In reality, it is a three-dimentional issue. The DOT section of Contract CA450A, Taipei-Sanchong Section, Taoyuan International MRT Line was selected for the study. The finite element analysis program, Plaxis 3D Tunnel, was introduced to generate a 3D analysis model for the simulation of a double-o-tube shield tunneling. Seven in-situ monitoring sections were selected for the study. The ground settlement and longitudinal deformation behaviors along the tunnel axis was plotted and compared with the ground settlement developed using the in-situ monitoring data and empirical equations. The analysis result demonstrated the feasibility of using Plaxis 3D Tunnel for ground settlement analysis on the construction of DOT shield tunnel. It is hoped that the results will serve as a reference for DOT shield tunnel construction and the experience to pass down to future engineers and researchers.