Wall soil stability analysis of vertical ridge unlined loess tunnel under earthquake

In order to obtain the shear failure laws of vertical ridge unlined loess tunnel under earthquake, according to dynamic and static analysis model, the shear strength reduction method and the ANSYS software were respectively applied to the unlined loess tunnel of small span for the static stability analysis and the dynamic response analysis under earthquake, and the shear strength safety factors of unlined loess tunnel were obtained, and the influences of calculation parameters like the tunnel span and the coverage soil thickness of tunnel and seismic intensity on the shear strength safety factor were discussed. The results show that: from perspective of loess wall soil material shear failure, the shear strength safety factors of shallow unlined tunnels which is small span, which are built in the loess region of 7 degree and 8 degree and 9 degree, are greater than 2.0.