Performance of an existing raft foundation rested on granular soils due to TBM tunneling process

Abstract

In urban areas, there is a necessity to evaluate the performance of existing structures during and after the construction of nearby tunnels. Therefore, a 3D numerical modeling technique is needed to consider the geometrical interactions between the tunnel and the existing structures. To validate the results of 3D numerical simulation for the tunneling process, the surface settlement trough resulted from the numerical model has been compared with field measurements of a selected case study (Second Heinenoord Tunnel in Netherlands). The 3D finite element model has also been used to evaluate the raft settlements and bending moments. The study is performed during and after the tunnel advancement process. In addition, the effect of related parameters, such as soil relative density (Dr), tunnel diameter (D), tunnel cover (Z), horizontal clearance between the raft centerline and the tunnel centerline (CL), raft inclination angle (i), and raft thickness (d), have been studied.