Rail Damage Mechanism And Control Measures Of Heavy Haul Railway

With the increase of the heavy haul railway transportation,the development of wear and damage of rails and wheels is accelerating,and wear and damage of the rails have become more serious.This has not only increased the work of maintenance and repair,but also threatened the safety of railways and affected the normal operation.The research on the damage mechanism and prevention and control measures of heavy haul rails is of great significance for improving the wheel-rail contact relationship and prolonging the service life of the rails.This paper mainly discusses the problem of rail damage in China's heavy haul railways.Based on the wheel-rail creep mechanism and the geometry relation of rail/wheel contact,the method of vehicle-track coupling dynamics is employed to study the damage mechanism of rails.Combined with the vehicle-track coupling dynamics method and a large number of field tests,the damage mechanism of the rail is studied.The main results and conclusions are as follows:(1)A theoretical model heavy haul railway vehicle-track coupling dyanmics model was established and verified.Typical rail damages and defects in heavy haul railways were investigated and analyzed.Based on the wheel-rail rolling radius difference?RRD₂and?RRD₃,the mechanism of wheel-rail creep and its influence was studied.The causes of side wear and rolling contact fatigue of rails in the heavy haul rails were analyzed and the control measures were given.A heavy haul vehicle-track coupling dynamics model was established,which can study in detail the influence of various parameters on wheel-rail contact and creep,and was verified from dynamics calculations such as nonlinear critical speed,straight curve passing performance and wheel-rail creep forces.The survey summarized the typical rail damages of China's heavy haul railways,including rail side wear and rail rolling contact fatigue.The mechanism of wheel-rail creep in vehicle operation was discussed,and the influence of the changes of the two parameters?RRD₂ and?RRD₃ on wheel-rail creep was studied.By using simulation calculation and experimental research,various possible solutions were analyzed,and it is recommended to improve the wheel-rail hardness,optimize the the wheel-rail profile,lubricate the wheel flange and gauge angle,and set an appropriate over superelevation for the outer rail.(2)The design theory and method of rail grinding profile for heavy haul railway is proposed,and a complete set of rail grinding technology for heavy haul railway based on minimizing wheel/rail creep is proposed,and performed the test on the rail using the grinding method.The test verifies that the proposed method can effectively extend the life of the rail.A comprehensive investigation was conducted on the rail wear and damage conditions of the Daqin line,and the rail profile of the experimental line was measured.Based on a large amount of field measured data,the rail grinding profile database was established,and the contact analysis of the wheel-rail equivalent conicity and contact position is carried out.Based on the static results and field tests,the design theory and method of rail grinding profile were put forward,and a complete set of rail grinding technology for heavy haul railways was formed.This mehtod was applied in multiple test sections and achieved the expected purpose.In addition,tests have also been conducted on rails using the grinding method.It is verified from rail tension,impact,residual stress,etc.that rails with a total weight of more than 1.5 billion tons still have similar performance to the new rails,indicating that the rail grinding method can effectively extend the service life of the rail.(3)The mechanism of rail friction control is studied and the rational values of friction coefficient of inner and outer rail in practical situation are put forward.The total friction control technique of rail is optimized and applied in typical workpoint.The influence of the wheel-rail lateral forces,wear number,wheel-rail creep rate,derailment coefficient and other performance indicators was analyzed.On this basis,the friction coefficient of the inner and outer rails was proposed.Reasonable value provided a theoretical basis for rail lubrication and optimizes the rail friction control technology.According to the rail friction control test on the Bao-Tian line,the feasibility and effectiveness of the method are verified.