Numerical Study On Seismic Analysis Of Submarine Tunnel

Accompanied with the rapid-developing economy and technique in recent China, there is a trend of building submarine tunnel. For instance, similar characteristics such as high water head, large cross section and complex structure exist in some completed or under construction submarine tunnel in Xiamen, HongKong, Shenzhen, etc. Meanwhile, several submarine tunnel will be designed and built in next 10 years and most of them will be set in those region with high intensity. Therefore, such a study of researching the seismic response of submarine tunnel is quite necessary in the present.This article was written on large-scale power CEL method of ABAQUS software to simulate fluid-structure coupling. The author has set up a three-dimensional finite element model with water, soil and tunnel according to the display algorithm included in mentioned CEL method. Factors like peak acceleration of seismic wave, the depth of buried, the direction of seismic wave incident and the depth of the water had been analysed as assumptions for researching the tunnels’seismic response characteristics (such as stress, acceleration and the displacement, etc.) The author has summarized the results as followed:(l)The dynamic response of tunnel will gradually increase with the rise of peak acceleration of seismic wave and it reflected into the changing rule of principle stress, vertical acceleration and displacement of tunnel structure.(2)Choppy trend of horizontal and vertical displacement appeared in the process of seismic. Besides, some residual deformation with different degree will also appeared on tunnels after the quake. It will block the operation of the tunnel and result in some negative effects to the waterproofing work of the tunnels.(3)Seismic response will gradually become flat with the increasing buried depth. In other words, the principal stress will be stable when the buried depth reached a certain point and it will almost have no effects on the dynamic water pressure.(4) In the lateral seismic wave input conditions, water, soil and mutual coupling effect is small, as the water depth increases, the tensile stress of tunnel structure appears the trend has been delayed, and vertical acceleration has a decreasing trend, from the perspective of the force described the greater of the water depth, the relative safety of a tunnel in the earthquake. While local shock waves along the vertical input coupling seawater and soil enhancement, impact on soil hydrodynamic pressure significantly, and with the water depth increases, the stress response of submarine tunnel become higher.