Study On Dynamic Response Of Tunnelunder Runway Under Earthquake

With the implementation of "One Belt and One Road" and the strategy of becoming a transport power and a civil aviation power,major cities at home and abroad are preparing for or have built a complex urban transport network composed of high-speed railways,rail transit,expressways and airplanes.It is more and more common for roads,rail transit and railways to run under airport runways.In this paper,the mechanical model of soil-tunnel structure is established,and the seismic dynamic response of tunnel structure is studied by shaking table test and numerical simulation.By establishing the dynamic model of tunnel structure under the combined action of aircraft load and earthquake load,the dynamic response of tunnel structure under the combined action of earthquake load and aircraft load was studied based on the FINITE element software ABAQUS.It was found that:（1）Through the comparative analysis of the shaking table test and the finite element numerical calculation,the reliability of the finite element simulation is verified by the test,and the variation law of the seismic dynamic response of the tunnel structure is obtained: the four corners of the rectangular tunnel structure belong to the weakest position,Instability failure is most likely to occur,and reasonable reinforcement measures should be taken to ensure the stability of the tunnel structure.（2）Based on the analysis of the relevant parameters of the aircraft load in the design of the airport runway structure,it is determined that the aircraft type is A380 passenger aircraft.According to "MH5004-2009 Design Specification for Cement Concrete Pavement for Civil Airports" and the relevant parameters of A380-800 aircraft,it is found that the aircraft taxiing state generates the largest load on the airport pavement,and the aircraft taxiing load acting on the top of the tunnel is determined.size.（3）The dynamic equation of tunnel structure under the combined action of aircraft load and earthquake load is established.It is found that the response of each part of the underground tunnel structure will be certain during the operation of aircraft,and secondary damage will occur at the vault,arch bottom and four corners of the rectangular tunnel in different degrees.Under the action of earthquake,the damage of underground tunnel structure is further aggravated,which will directly threaten the safety of the whole tunnel structure.（4）By studying the dynamic response of tunnel structure under the combined action of aircraft load and seismic load,it is found that the response of tunnel structure vault is obviously larger than that of the arch bottom,which is prone to instability failure phenomenon,and the dynamic response of tunnel structure is related to the action position of aircraft load.Under the combined action of aircraft load and earthquake load,the response of tunnel structure decreases gradually with the increase of buried depth and lining thickness.Therefore,the tunnel safety can be guaranteed by changing the buried depth or lining thickness of tunnel structure,which provides reference for future related engineering and research.