Study on Influence of Fault Dip Angle on Tunnel Lining

The tectonic plate movement causes more Earthquakes of small to medium magnitude in Himalayan regions so it is very essential to study the behaviour of underground structures like tunnels under fault movement. The fault dip angle as well as fault thickness on the tunnel lining surrounding rock are the important parameters that control the damage to tunnel lining. The main objective is to study the effect of dip angle on the tunnel lining during fault movement. In the present study, three dip angles 60, 75 and 90 degree with the fault thickness of 25 m are considered. Three-dimensional finite element programming is used for modelling the tunnel-soil interaction. The fault movement is activated by dip slip displacement loads and the results are interpreted. It is observed that increasing the angle of dip increases the stresses in the tunnel lining. With increase in the dip angle, the location of plastic zone slightly shifting towards the footwall side due to the concentration of compressive stresses in the tunnel lining near the hanging wall and fault area.