| Several large earthquakes have occurred in the past two decades,which caused a large number of serious damage of underground structure and loss of property,but the near-fault region is often suffered the most serious earthquake damage in many places.Our country has a lot of seismic belt and earthquake faults,many cities are close to the faults or in the seismic belt,and Some large engineering structures are often across the faulting layer. Therefore, it is necessary to study the earthquake resistance and damping theory of tunnels in the near-fault region,and establishing relevant shock absorption measures to guide engineering practices.Dynamic response rules of tunnels under earthquake are mainly studied by analyzing the results of the physical model test(including indexs of spectrum characteristics and peak of acceleration,principal strain of lining,the maximum displacement,surrounding rock pressure and so on)in this paper,and compared with numerical simulation at the same time.The main work is as follows:①The suitable material of tunnel lining and surrounding rock is founded by test of similar material proportion,and completing the design of the test scheme,which includes model making,test point arrangement,choice of seismic wave,design of the loading scheme,data acquisition and so on;②Shaking table model test is conducted,and by analyzing the results of the test,the following conclusions are drawn:the vault should be the key part of earthquake resistance protection for the tunnel structure;along axis of the tunnel,shallow-buried section needs the important fortification,especially for the openings position;because of the seismic amplification effect,higher position of the slope also need the fortification;③Numerical simulation is conducted by ANSYS,and compared with the physical model test, the results show that numerical simulation and experiment has a similar change law,and also verify the accuracy of the test results. |
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