Study Of Dynamic Responses Of Overhead Transmission Tower-line Systems To High-speed Train-induced Ground Vibration

The continuous increase number of China’s power grid infrastructure and transportation infrastructure has led to an increasing cross-over between transmission lines and high-speed railways.The interaction between wheel and rail has a great impact on the track,resulting in a large vibration at the track when the high-speed train runs across the section.And then the vibration is transmitted to the surrounding soil layer through the track,subgrade,which causes the secondary vibration of the transmission tower line structure crossing the section and affects its normal use.In this paper,the ICE3 trains were taken as research object,which is commonly used on highspeed railway lines in China,aiming at the occurrence of accidents such as line drop when crossing over sections in recent years.Then,numerical simulation method was used to study the dynamic response of the transmission tower line structure under vehicle-induced ground vibration.Finally,the influence of different train speed,type of soil and distance from tower to track on the dynamic response of transmission tower line structure under vehicle-induced ground vibration was analyzed.The main research contents and conclusions were as follows:(1)The influence of track irregularity on vehicle-induced ground vibration was analyzed based on the finite element model of train-track-freefield,and then the influence of different soil and train speed on vehicle-induced ground vibration and its attenuation characteristics were studied.The results showed:The vehicle-induced ground vibration decays quickly near the track,while slowly at the ground surface 30m～50m away from the track and had a tendency of secondary amplification.Track irregularity had a great influence on the vibration response of subgrade surface,but its influence on the vibration of ground surface beyond 4.5m of track can be neglected.The response amplitude of vehicle-induced vibration on the surface of soft soil site was larger than that of hard soil site,while the frequency distribution of surface vibration on hard soil site was broader than that on soft soil site.The amplitude of the vibration response of the ground surface increased with the increase of vehicle speed,while the impact between the wheel and rail near the track decreased,and the secondary amplification trend of the vibration response of the ground at a distance from the track decreased.(2)Taking 2A-ZM1 transmission tower line structures as research object,the finite element model of "three towers and two lines" system was established to study the effects of different types of soil,distance from transmission tower to track and vehicle speed on the vibration response of transmission tower line structure under vehicle induced ground vibration.The results showed that the influence of the distance from the transmission tower to the track on the response of the cross line transmission tower line structure under vehicle induced ground vibration was greater than the train speed.Comprehensively considered the train speed,the type of site soil,the distance from the transmission tower to the track:The Cross Railway transmission tower had the largest vibration response when the train speed was 250km/h～400km/h and the distance to the track was within 30m,underground in the soft soil field;While underground in the hard soil site,the vibration response of Cross Railway Transmission Tower was the largest when the train speed was 250km/h～350km/h and the distance to the track was within 40m.