Experimental study on acceleration response laws of shallow-buried bias tunnels with a small distance

Based on the similarity theory, a physical testing model with scale of 1:10 was designed and fabricated. The Wenchuan wave (WC-XZ), Darui artificial wave (DR-XZ) and Kobe wave (K-XZ) were adopted as excitation waves which was XZ directions (horizontal and vertical loading at the same time). A series of shaking table tests were carried out to study the effect of the types, directions and peaks acceleration of the seismic waves on the acceleration response laws of the shallow-buried bias tunnels with small distance. The results show that: (1) in the horizontal direction, the types of the seismic waves have a little effect on the acceleration response, but the law is opposite with Kobe wave being the most serious, followed by Darui artificial wave and Wenchuan wave in the vertical direction. (2) The existing slope has a significant effect on the acceleration response of the right hole which is different from that of the left hole. (3) The acceleration response of the tunnel in the vertical direction is more severe than that of the horizontal direction and the acceleration amplification factors in vertical direction are is generally 1.02-3.94 times that of the horizontal direction. (4) in the seismic design of tunnel, different seismic measures should be adopted in different directions. The results have a significant reference for the anti-seismic design of the tunnel.