The Effect of Operational Parameters Affecting Ground Surface in excavation with Earth Pressure Balance Shield Machine-EPBM (the case of Tehran Subway Southern Extension Tunnel- Line 6)

In this study, the effect of some of the most important operational parameters of the tunnel boring machine (EPBM) has been investigated at the time of the tunnel excavation on the ground deformation and surface subsidence. The basis of this research is the finite difference method (FDM) using FLAC3D software. The numerical model was first constructed based on geotechnical parameters (physical and mechanical characteristics) of the Tehran Subway Southern Extension Tunnel-Line 6 and then calibrated and verified based on the "invisible tunnel" method. The results showed that by decreasing the boundary pressure on the face and the annulus, there is no significant change in the increase in the level of the surface subsidence. Also, the results of parametric analysis of the injection pressure of the grout showed that applying the pressure of the grout equivalent to the vertical geostatic stress relative to the horizontal geostatic stress in the tunnel face has more effect on the control of surface deformation and subsidence.