Parametric Study on Stability of Tunneling Excavation Face via Fluid-Solid Coupling Simulation

In case of shallow buried depth and high hydraulic pressure, it was very difficult to control excavation face stability during shield tunneling, frequently followed by catastrophic results (e.g., significant subsidence due to collapse of tunneling face). Based on three-dimensional (3D) numerical parametric analyses validated by centrifuge model test results, this study investigates the effect of supporting pressure on tunneling face stability, in terms of deformation of tunneling face and ground settlement and so on. To simulate the cases featuring high groundwater level, complete fluid-solid coupling calculation was taken into account in the numerical analyses. This was achieved by assuming that shield was in a shutdown state; meanwhile, by reducing excavation pressure gradually and setting the seepage time, the relationship between the stress-strain of the strata surrounding shield and supporting pressure of tunneling were explored.