Track Dynamic Behavior And Its Control Technology In Throat Area Of Electric Multiple Units Depot In High-speed Railway

By the end of 2019,there are more than 139,000 kilometers of railways in operation in China,and 66 electric multiple units(EMU)depots had been built.The design standard of the railway in EMU depot is low,and the track curve radius of turnout area is small,and the passing ability of the throat area is insufficient.On small radius curve,the line is greatly affected by the impact of trains,which leads to frequent diseases,bad line conditions,difficult track maintenance,and frequent derailment accidents.The speed of EMU is restricted by the capacity of the throat area,schedule arrangement,security prevention and control,transportation economy and other factors.On the other hand,the capacity of the throat area is related to the structure of EMU,line state,wheel-rail relationship and other associated conditions.Therefore,it is necessary to conduct an in-depth study on the dynamic behavior and control technology of the throat area of EMU depot in combination with the EMU models.In this paper,combining theoretical model and field test,the safety,dynamic behavior and wheel-rail wear of small radius curve and small number turnout in throat area were studied.The main research work is as follows:(1)Based on the small radius curve and small number turnout in Guangzhou East and Beijing South EMU depot,the dynamic characteristics in throat area of EMU depot were obtained by field test of many kinds of EMU.The results show that the derailment coefficient and the lateral force of the wheel and rail are easy to approach the limit value,which indicates that the EMU has a great risk of derailment and lateral wheel-rail interaction when passing through the throat area.In addition,The dynamic behavior of different types of EMU when it passes through the throat area is significantly different.Different wheel tread profile and vehicle positioning stiffness of EMU will significantly affect the dynamic performance of the vehicle in the throat area.(2)Based on the multi-body dynamics theory,considering the coupler buffer device,different EMU models named CRH380A,CRH380B,CRH5 and 25T rolling stock were established.The flexible track model was established based on finite element method.Considering the wheel and rail contact relationship of multi-point contact algorithm,the space coupling dynamic analysis models of the vehicle-small radius curve / small number turnout were established.Based on the Archard model of wear calculation,the rail wear prediction model of small radiu curve was established.(3)Based on theoretical analysis and field test,the dynamic behavior and control technology of small radius curve of EMU deopt were studied.1)The safety performance of high-speed EMUs at low speed passing through the typical reverse curve of small radius was evaluated,and the maximum permissible speed under various vehicle types,different line conditions and track irregularity conditions was given.The increase of the curve radius can improve the safety performance of the EMU passing through the small radius curve.2)Based on the theory of Archard wear,two practical lines with small radius in Guangzhou East and Taiyuan South EMU Depot were selected,the rail wear of small radius curve was predicted and analyzed.The results show that: for the small radius curve,the order of rail wear size from big to small is QZ point,YZ point and ZY point.For different curve radii,the cumulative wear depth is R200,R250,R300 and R350 from the largest to the smallest.The range of rail wear decreases with the increase of vehicle speed.The range of wear of the ZY point is the largest.3)Based on technical parameters of different types of EMU,wheel tread and vehicle posioning stiffness,the dynamical behavior and control technology of small radius curve was studied.The wheel-rail safety and wear conditions of the four vehicle types are CRH380A,25T,CRH5 and CRH380B in descending order.LM and LMA wheel tread has the lowest equivalent taper and the best adaptability.When the positioning stiffness is large,the lateral effect of rail and wheel is large.The influence range of positioning stiffness difference on various indexes of lateral action is more than 10%.4)Based on the track structure,the dynamic behavior control technology of EMU of small radius curve was studied.The CHN60 rail is obviously better than the CHN50 rail in the maintenance of the track geometry and the load transmission on substructure;the dynamic performance of the vehicle will increase with the increase of rail wear,the derailment coefficient is mainly affected by the rail wear in the curved line.Rail lubrication will significantly reduce the derailment coefficient and lateral forces of wheel and rail.After rail lubrication,the derailment coefficient at each position of the curve is lower than that before the rail lubrication,and the lateral force of wheel and rail decreases greatly in the middle of the curve after rail lubrication;in the middle and exit position of the curve,when the track surface is wet,the lateral effect of EMU on the track is significantly less than the dry state of the rail surface.(4)Based on theoretical analysis and field test,the dynamic behavior and control technology of small number turnout of EMU deopt were studied.1)The dynamic indicators of small number turnout change violently in the switch and frog area,and the peak appeares in the point position of frog.When the lateral passing speed reaches or approaches the design speed,the unloading rate and other indexes exceed or approach the limit requirements,indicating that there is a certain safety risk when the EMU passing through the branch line of the turnout.2)Based on e technical EMU parameters of different types of EMU and vehicle posioning stiffness,the dynamical behavior and control technology of small number turnout was studied.From good to bad,the dynamic behavior,safety condition and wear level of type 9 and 12 of turnout are CRH380A,CRH5 and CRH380B.In the middle of the guide curve,the lateral effect of CRH380A with small positioning stiffness on the turnout was significantly smaller than that of CRH380B.3)Considering the characteristics of turnout structure,the dynamical behavior control technology of small number turnout based on turnout structure type was studied.The CHN60 rail is obviously better than the CHN50 rail in every dynamic indicators;compared with fixed frog structure,movable point frog can effectively reduce wheel-rail interaction,wheel-rail wear and the risk of derailment.4)The irregularity management limit of the guide curve of turnout was determined.When there is a compound irregularity in the guide curve,the safety risk is greater than the horizontal and rail irregularity.