Abstract: The seismic response of a tunnel in fills is numerically simulated. The effect of the seismic loadings in the high earthquake intensity zones on the stress in the tunnel lining structure in fills are modeled under different lining thicknesses, concrete strength values and fill thicknesses. The results indicate that, under the seismic loading, lining and fill thicknesses are the two major factors that are affecting the bending moment and shear force in the tunnel, especially, at the joint of the bottom slab and the mid wall. When the strength of the lining concrete is greater than 30MPa, the influence of the concrete strength on the stress in the tunnel is minimal. Unbalanced fill above the tunnel should be avoided and the horizontal internal support should be added to improve the stress state in the tunnel.

Key words: Tunnel in Fills, Seismic Responses, Numerical Simulations