Research On Shaking Table Model Test Of The Rock Tunnel Affected By Fault Movement

In the large-scaled infrastructure construction, it is becoming more and more ordinary that underground construction especially tunnels are built across faults. The engineering problems caused by faults movement have become more and more popular.Based on the fact that tunnel has been severely destroyed by fault movement under strong earthquake, the paper carried out the study on shaking table test about the seismic behavior of tunnel across the fault under the action of earthquake. Some creative conclusions are obtained as follows:(1)Verify the similar material mixing of barite powder, iron ore power, quartz sand and gypsum is suitable for the rock with geometric similarity ratio of 100. Due to the high density of the material, it can easy convert the similarity ratio between model and prototype. Elastic modulus and compressive strength of the material is lower so that can simulate an actual brittleness of rock better.(2) The dynamic response of rock in hanging wall and footwall of fault is different and the tunnels through fault with different dig angle of 300、450、and 600 have different dynamic response when the seismic wave was loaded. The tunnels across the fault with 450 dip angle have the greatest dynamic response of surrounding rock.In the model box with the fault of dip angle with 300, the dynamic response of surrounding rock is in the middle. In the model box with the fault of dip angle with 600, the dynamic response of surrounding rock is least. Through the analysis of acceleration time history of the surrounding rock and the surface strain of tunnel in hanging wall and footwall of fault, it is found that in the same position of the surrounding rock, the peak ground acceleration in the depth of tunnel axis in hanging wall is 2.2～2.5 times larger than that in footwall of fault and the surface strain of tunnel in the hanging wall is greater than in the footwall. So the seismic effect of hanging wall of fault is greater than the footwall of fault.(3) The surrounding rock has different response to different seismic wave. Through the analysis of the peak acceleration response of surrounding rock with the Kobe and El-Centro waves, it is found that with the increase of the amplitude of the input seismic motion, the peak acceleration response of surrounding rock increases gradually. In the same position of the surrounding rock, the peak acceleration response of surrounding rock with El-Centro wave is 2.5-3.5 times larger than Kobe wave. So it is concluded that the surrounding rock has a greater dynamic response with El-Centro wave than dynamic response with Kobe wave.(4) Through the analysis of the surface strain of tunnel, it is indiected that with the increasing of amplitude of wave, the surface strain of tunnel increases continuously and the surface strain of tunnel is getting smaller by the stiffness of the tunnel getting bigger; it increased firstly and then decreased when the distance of measuring point on the surface of tunnel and the fault increased.