Research On Dynamic Response Of Hollow Lining Of High-speed Railway Tunnel

During the operation of high-speed railway tunnel,the lining body will inevitably appear various diseases under the influence of various factors,such as lining cracks,lining void,leakage,etc,and the lining void is more harmful in the three factors.Under the condition of the lining void,the train vibration load or earthquake could cause lining damage,which makes the stability and durability of lining greatly reduced,threatening the safe operation of the train.Therefore,this paper analyzes and studies the dynamic response of the cavitation lining under the train load,the seismic response of the cavitation lining under adverse working conditions and the fatigue life of the cavitation lining under train load.The main research results are as follows.(1)Dynamic displacement and acceleration increase with the increase of the three void arc length,void length and void depth.The peak value of the first principal stress increases with the increase of void arc length and void depth,and decreases with the increase of the cavitation length.The length of the void arc has the greatest influence on the dynamic displacement,acceleration and the first principal stress,followed by the void length,and finally the void depth.(2)There is a certain magnification effect in the displacement response and acceleration response of the seismic response under the lining void.The amplification coefficient is 1.033 under the vault void and 1.097 under the shoulder void.In terms of the first principal stress,the void of the lining causes the stress at this position to be transformed from compressive stress to tensile stress and the maximum tensile stress is 1.826 MPa.(3)By comparing the dynamic displacement,acceleration and the first principal stress in the seismic response and the train vibration response,it is found that the dynamic displacement fluctuation of the lining is not the same,while the acceleration fluctuation is similar.Moreover,the relative displacement,acceleration and first principal stress of the lining under different seismic peak accelerations are much larger than the dynamic response of lining under train vibration.(4)The most unfavorable parts of the lining in all working conditions appear in the following three positions: the inside and outside of the void boundary and the void center.And the fatigue life of most linings under arch shoulder void is smaller than that of vault void,and the fluctuation is larger than that of vault void.At the same time,the fatigue life of three working conditions under arch shoulder void does not meet the design life of the structure for 100 years.