Research On Response Spectrum Of High-speed Railway Track-bridge System Considering Ground Motion Characteristics

With the rapid expansion of China’s high-speed railway network,high-speed railways inevitably pass through areas with frequent earthquakes,and the geological environment of different regions is different,which will inevitably affect the shape of the response spectrum curve,and then affect the seismic design of high-speed railways.In order to provide a response spectrum that accurately reflects the ground motion characteristics of the southwest region for the seismic design code of highspeed railways,this paper will collect the main ground motion data in the southwest region in recent years,and use statistical methods to study the correlation between the source parameters and the ground motion characteristics of the southwest region.Earthquake prediction model,proposed seismic response spectrum suitable for high-speed railway in southwest China,and compared with the current code.The main research contents are as follows:(1)Based on the Wenchuan earthquake,Lushan earthquake,Jiuzhaigou earthquake,Kangding earthquake data and the information of each recording station,use statistical methods to analyze the correlation between fault distance,site type,fault type and fault rupture area and ground motion characteristic parameters PGA and PGV.(2)Calculate the average response spectrum of the actual ground motion in the acceleration interval corresponding to different fortification intensity,and compare and analyze it with the current standard response spectrum.The results show that the platform value of the current seismic standard response spectrum is lower than the actual situation.(3)Analyze the influence of the actual ground motion in southwest China,such as the fault distance,site type,fault type and fault rupture area,on the response spectrum platform value and the attenuation index of the descending segment.Based on the characteristics of ground motion,the seismic design response spectrum of high-speed railway track-bridge system suitable for southwest China is proposed.(4)Study the difference between the current normative response spectrum and the modified response spectrum,select seismic waves according to the combination of different fault distances and site types,and study the seismic response of the high-speed railway track-bridge system under the action of the two types of ground motions.The results show that the structural response caused by the seismic wave selected according to the modified response spectrum is larger than the current standard response spectrum.Conduct relevant research on the characteristics of ground motion in the southwest region,explore the source parameters that affect the response spectrum,propose a seismic response spectrum that is closer to the actual situation,and analyze the response of the high-speed railway track-bridge system under different ground motion characteristics.Provide reference for the coordinated seismic design of high-speed railway track-bridge.