Study On Structural Vibration Response Of Sluice Caused By Rail Transit Load

With the rapid development of rail transit in China,a large number of railway tracks pass through the farmland area.When the distance between rail transit routes and farmland water conservancy facilities is close,it is difficult to avoid the impact of rail transit on farmland water conservancy facilities,which is not considered in the current design specifications.Compared with other buildings,farmland sluice in hydraulic structure is smaller in size,thinner in structure and more sensitive to vibration.However,there are few researches on the vibration response of sluice.The vibration response law of sluice structure caused by train operation and its influence on structural safety and durability are worthy of further study.In order to find the vibration response law of sluice structure caused by train operation,the acceleration time history of vibration response at different positions of sluice structure was obtained by field observation,and then the dynamic response analysis model of sluice structure was established by using large finite element software.Based on this model,the random vibration analysis of sluice structure was carried out,and the correctness of the model was verified by the measured data.The influence of vibration response of sluice structure at different distances on structural safety was evaluated.Combined with unfavorable working conditions,the random vibration fatigue analysis of sluice upper working bridge structure was carried out.The main achievements are as follows:1.Field observation of acceleration time history of sluice structure vibration response caused by rail transit is completed.The vibration acceleration time history of some key points of the sluice structure when the train passes is collected.Based on the analysis of power spectrum and acceleration vibration level of the measured data,it is preliminarily determined that the upper working bridge structure of the sluice is a vibration sensitive part.2.Three-dimensional solid finite element analysis model of sluice structure is established.Through the ANSYS Workbench platform combined ANSYS classical version and Space Claim Direct Modeler software,a finite element model of the whole structure is established according to the actual size of the sluice structure at 1:1,considering the fluid-solid coupling between the water body and the structural members.The viscoelastic artificial boundary is applied at the truncated surface of semi-infinite foundation soil,and the calculation accuracy of the model is high.3.Random vibration response of sluice structure in rail transit environment is analyzed.Based on the results of modal analysis,the natural frequencies of sluice structure in dry and wet conditions are compared,and the active change areas of equivalent stress and displacement of structures are determined.The PSD values at the key points of the sluice superstructure in the model are extracted,which are in good agreement with the measured data,and verify the accuracy and rationality of the model.Considering the superposition effect of random vibration and initial static force of the structure,the change results of internal stress and displacement of the sluice structure under different distances and different working conditions are compared and analyzed.The change law of vibration response of the sluice structure under the influence of distance factor is summarized,and the most unfavorable working condition combination is obtained,that is,the left side span and the middle span gate are opened at the same time,at which time the maximum stress and displacement of the structure occur,but it is still in the safe use range.4.Fatigue analysis of upper working bridge structure of sluice under rail transit environment is carried out.Using Ncode Design Life professional fatigue analysis software,the vibration fatigue analysis flow is established,the S-N curve of concrete material is fitted,and the load spectrum is downloaded from different distances.Based on the theory of linear fatigue cumulative damage,the fatigue life of the upper working bridge of sluice under the most unfavorable working conditions is analyzed,and the influence of rail transit load on the durability of sluice structure is evaluated.