| The environmental vibration diseases caused by the train running in the curved section of the subway are frequent,and the environmental vibration response is more complex than that of the straight line,which needs further study.On-the-spot measurement was carried out in the curved section,and the vehicle-track coupling dynamic model and the dynamic finite element analysis model of track-tunnel-soil-building under the moving load of trains were established.The influence of train vibration on the adjacent ground and buildings in the curved section of subway tunnel was studied,and the main results were as follows:(1)Carry out on-site vibration test on the ground and buildings near the curve section of the subway.The results show that the half-peak value and effective value of the horizontal acceleration of the ground measuring points in the curve section are 0.9～2.4times and 1.1～2.4 times of the vertical,respectively.The main frequency of horizontal vibration is 40Hz～150Hz,and the main frequency of vertical vibration is40Hz～120Hz.The main vibration frequencies of each floor of the building are distributed in 20 Hz～ 60 Hz;The corresponding frequency distribution of the maximum frequencydivided vibration level is 31.5Hz～40Hz,with a value of 60.2d B～72.7d B.The first floor of the building has the largest frequency-divided vibration level,and the corresponding center frequency is 31.5Hz,with a value of 72.7d B.Many floors have not met the requirements of the code limit.(2)The dynamic model of vehicle-track coupling is established by SIMPACK and ANSYS joint simulation.Based on the measured track irregularity,the time history curve of train wheel-rail force is obtained.Taking wheel-rail force as vibration excitation input,a three-dimensional dynamic analysis model of track-tunnel-soil-building is established by MIDAS GTS NX,and the rationality of the model is verified by comparing with the field test results.(3)The influence of the running speed of the train on the vibration response of adjacent buildings in the state of curve superelevation equilibrium is studied.The results show that the maximum frequency-division vibration level of the building increases with the increase of the curve superelevation value.Compared with the superelevation equilibrium state,the maximum frequency-division vibration level in the superelevation state is 2d B～4d B higher in the vertical direction and 6d B～11d B higher in the horizontal direction.In the super-balanced state,the maximum vibration level of building frequency division is not much different from that of straight line.With the increase of curve running speed,the vibration level of adjacent buildings increases continuously.When the speed is increased from 40km/h to 60km/h and 80km/h,the maximum vibration level of each floor is increased by 2.1d B～3.5d B and 5.1d B～7.5d B respectively.(4)Based on an engineering example,finite element simulation is adopted to calculate and analyze the vibration reduction effects of various vibration reduction and isolation technologies.The results show that when Vanguard vanguard damping fastener is used,the peak section of building vibration shifts to low frequency,and the maximum insertion loss of frequency division vibration level is 13.9d B～16.0d B.The depth of the ditch should reach 3m below the tunnel floor,which has a good effect of vibration reduction and isolation.The maximum insertion loss of the building frequency division vibration level is 13.0 d B～ 13.6 d B.The maximum insertion loss of frequency division vibration level of buildings is 11.3d B～12.1d B under the condition of filling ditch with foam plastic.For the vibration with frequency below 10 Hz,the effect of vibration reduction and isolation by empty ditch is weak,which can better reduce the vibration above 10Hz;In the frequency range of 20Hz～100Hz,the foam-filled ditch is better than that of lightweight aggregate concrete.It is suggested that the foam-filled ditch with a depth of 21 m and a width of 0.5m should be used. |
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