Dynamic Response Of High-speed Railway Subagrade-ballastless/Ballasted Track-train System Under Erathquake

With the implementation of ‘China High Speed Rail Going Global’ strategy and ‘A Country with Strong Transportation Network’ strategy,high-speed railway(HSR)construction is in full swing in China and other parts of the world.As most part of China is located in areas with high earthquake intensity exceeding VII,this means the probability of encountering an earthquake for a running train will greatly increase and it would be a major threat to the train running safety.However,the research on subgrade of HSR concentrates on the simple subgrade instead of the subgrade including of upper structure coupling,and the subgrade influence on the dynamic response of train is not considered.There are few corresponding experimental researches on the dynamic response of subgrade-ballastless / ballasted track – train system.This paper studies the dynamic response of high-speed railway subagrade-ballastless/ballasted track-train system under earthquake using shaking table and numerical simulation software.Also,the train running safety is studied with different earthquake and different train running speed based on the verification using the numerical simulation software.The main research work of this paper and results are as follows:1.The seismic response research of subgrade with ballastless track introduces the process of shaking table model test in detail.The acceleration response,earth pressure response and displacement response of soil under horizontal and vertical seismic waves are studied.The earthquake response of slope is studied,and the slippage risk of track slab is evaluated.The potential damage of subgrade soil under earthquake is proposed2.The seismic response research of ballastless track-train on subgrade is carried out based on shaking table test.The derailment factor of the train under different seismic waves are studied,and derailment risk of the train under current parking threshold value is researched especially.The derailment process is described and the critical derailment conditions and wheel-rail complete detached conditions for the following vehicles subjected to different seismic waves are also obtained.3.A large scale shaking table test was carried out on seismic response of subgrade-ballast track-train system.The horizental and vertical dynamic response of the system are studied.The effects of ballast and the derailment characteristics of the train under the current parking threshold value were studied.The critical derailment conditions and wheel-rail complete detached conditions for the following vehicles subjected to different seismic waves are also obtained.4.FLAC3D numerical simulation software was used to verify the reliability of the subgrade model experiment and the results also verified the potential damage analysis of the tested subgrade.The track-train model established using SIMPACK dynamic simulation software used the acceleration response of the subgrade top in experimental model as the input of the simulation model.The derailment factor and wheel lateral force were obtained under current parking threshold,and the results were compared with experimental results.The train running safety under different types of seismic waves,different intensity of seismic waves,and different train speeds were studied.The results show that the current code is conservative and reasonable.The results of this paper can provide guidance for further research on high-speed railway earthquake early warning.