Research On Seismic Threshold Of Catenary System In Subgrade Section Of High-speed Railway

There are many seismic disasters in our country,and the contact network system is prone to accidents such as catenary disconnection and pillar lodging due to seismic,which seriously affects train traffic safety.The seismic early-warning and monitoring system can automatically cut off the power of the contact network system in advance through the method of threshold warning to reduce the loss of seismic disasters.This paper proposes a threshold value for the contact network system of subgrade section of high speed railway.The main research contents are as follows:Firstly,a simulation model of contact network system of subgrade section is established with the ABAQUS software,and through the modal analysis under the seismic-free conditions,the vibration modes and frequency parameters of the system are obtained.And compares the modal analysis results with the field tests data.The results show that the modal analysis results under the seismic-free conditions are relatively closed to the tests data,with a maximum error of 2.36%,which verifies the rationality of the simulation model.Secondly,uses seismic waves with different frequency spectrum characteristics or different seismic intensities to excite the contact network system of subgrade section,the seismic response law of the system under different seismic parameters is obtained.It is concluded that the superior frequency of the Tianjin wave is approached to the natural frequency of the system,and the vibration response of system is larger;Any of the system's seismic responses generally enlarge with the augment of the seismic intensity.Thirdly,compare and analyze the seismic response laws of different system types,different suspension types,different pillar types and different subgrade heights to the contact network system of subgrade section.Consider the actual situation,then compare and select the most unfavorable parameter working conditions,and choose the copper wire system type,the elastic chain suspension type,the H240 pillar type to carry out the simulation calculation of the threshold value researches.Fourthly,aiming at the larger defects of traditional analytic hierarchy process that is influenced by individual elements,the improved AHP based on threshold elimination is proposed,that is,for a certain element,calculate the weighted sum of each scale,and eliminate the expert evaluation below the threshold.The improved AHP has higher credibility,and the seismic intensity and the subgrade height are the weak links that affect the safety to the contact network system of subgrade section.Fifthly,according to the seismic safety evaluation standard of the contact network system of subgrade section,considering the combined working conditions of the anchor pillar and the most unfavorable parameters,four types of typical seismic waves are selected to excite the system,and the maximum safety threshold allowed of the system is obtained.Furthermore,it fits multiple safety curves,divides the safety zone and the dangerous zone,and proposes a simple and reliable threshold value that can cover various working conditions.That provides reasonable suggestions for the threshold value warning of the high-speed railway of the seismic early-warning and monitoring system.