Study On The Train Vibration Response Of Cross Tunnel Structure Of Subway With Connecting Aisle

With the development of urban rail transit in China,the subway has gradually become the main mode of transportation for major cities in China.Aiming at a certain city subway interval period of structure in the shield tunnel,the dynamic response characteristics of the tunnel structure was studied by using theoretical analysis,numerical simulation and similar model test method.And the dynamic response of the structure of the cross tunnel under the condition of sulfates corrosion in the operation process is considered.The main research contents and results are as follows:(1)Based on the ABAQUS finite element software for numerical simulation,by applying the train vibration load at the wheel position of the subway train formation and applying a specific running speed to the train,the running course of the subway train in the structure cross shield tunnel is simulated.(2)The characteristics of the main stress,vertical acceleration,vertical velocity and vertical displacement of the tunnel segment structure are analyzed when subway trains are traveling in the structural cross-tunnel.The results show that the vibration response of the road tunnel is the largest,the vibration response in the connecting aisle is the second,and the minimum vibration response is the untuned tunnel.For the road tunnel,the vibration response of the arch bottom is the largest,and the vibration response of the dome is the smallest.From the bottom to the top,the vibration response gradually decreases.(3)A structural cross-tunnel device for train vibration test was designed and constructed.Through the excitation of different positions,the vibration response characteristics of cross-section tunnels were studied.The results show that the test result satisfies the law that the vibration response is smaller as the distance from the exciting vibration location is longer,and the vibration response attenuation strength along the longitudinal direction of the tunnel is greater than the vibration response attenuation intensity along the transverse direction of the tunnel.(4)Through the combination of similar model tests and numerical simulations,the dynamic response characteristics of the lining and the surrounding rock of the structure-cross shield tunnel are compared and analyzed from the time and frequency domains.The results show that the acceleration amplitude will be attenuated during the transmission of vibration acceleration.And the response attenuation of the vibration acceleration in different frequency bands is different,specifically the attenuation degree of the high frequency band is greater than the attenuation degree of the low frequency band.(5)The variation law of elastic modulus,ultimate compressive strength and ultimate compressive strength of tunnel segment concrete under sulfate corrosion is studied.The dynamic response characteristics of the cross shield tunnel during structure operation are obtained under different corrosion time.