Improving Ground geomechanical characteristic for Ground movement control in urban zone

Tunneling operation Analyses in 3D conditions is a widely used method to calculate tunneling induced settlement profiles as well as soil structure interactions. The potential of damage, for the surface and/or underground structures can be estimated using powerful finite difference method (FDM). However, setting up a realistic model that would be able to achieve this goal is rather difficult. In this paper, a 3D FDM analysis has been conducted to assess tunneling induced settlement and stress redistribution phenomena along with movements around shallow soft ground tunnels excavation. Displacements recorded during construction of the Line 1 subway Tunnel in Tehran formation were compared with the predicted values to validate numerical estimations. Back analysis carried out on FDM results of soil zone, the data groups that have best accordance with recorded measurements were selected. The results show that grouting has significant effect on tunnel stability and back analysis results have accordance with soil geotechnical properties and grouted zone. Soil strength parameters improved several times and soil permeability decrease significantly. Surveying groutability showed that an increasing in grouting pressure, makes grouting possible in this zone

Keywords:

grouting , FDM , settlement , back-analysis , grout ability