Numerical modelling of tunnelling induced ground deformation and its control
V.B. Maji；A. Adugna
Earth Pressure Balance (EPB) ； Face pressure ； Ground movement ； Critical support pressure ； Surface settlement ； Subsidence
International Journal of Mining and Geo-Engineering
|Volume or Term/Year and Month of Publication||
50卷2期（2016 / 12 / 01）
183 - 188
Tunneling through cities underlain by soft soil, is commonly associated with soil movement around the tunnels and subsequently surface settlement. The predication of ground movement during a tunnelling project and optimum support pressure could be based on analytical, empirical or the numerical methods. The commonly used Earth Pressure Balance (EPB) tunneling machines, make use of the excavated soil in a pressurized head chamber to exert a support pressure to the tunnel face during excavation. This face pressure is a critical paramater in EPB tunnelling because the varying pressure can lead to the total failure and collapse of the face. The objective of the present study was to evalute the critical supporting face pressure and grout pressure by observation of the vertical deformation and horizontal displacement of soil body during tunneling. The face pressure and grout pressures were varied to see how they might influence the magnitude of surface settlements/heave. A numerical model using PLAXIS-3D Tunnel software package was developed to analyze the soil movement around the tunnel which can involves different geotechnical conditions. The ground surrounding the tunnel was found to be very sensitive to the face pressure and grout pressure in terms of surface settlementand the possibility of collapse in the body of soil.