| Although the axle load of 36-40 t has been generally carried out in heavy haul railway developed countries,such as the United States,Australia,while 25 t axle load railways have still been used in China.Therefore,the researches on heavy haul railway running 40 t axle-load trains do not only good to the future of China’s heavy transport system,but also greatly contributes to China’s "go global" strategy.Based on the analysis of the design parameters of the ballast track on the heavy haul railway at home and abroad,the coupling model of vehicle-track is established in this paper,which as a tool to explore the design of the ballasted track criteria to complete the key parameter design.The main contents and conclusions of the thesis include:By collecting and analyzing the structural parameters of major heavy haul tracks around the world,the author finds that under the existing construction and maintenance level,the design of 40 t axle weight is feasible.In order to meet the requirements for 40 t axle load,speed up to about 90 km / h,the rail track structure specifications typically must be 68 kg/m or more,strength of 1300 MPa,0.6 m sleeper spacing,ballast thickness not less than 0.3 m,also with sub-ballast which must be thcik enough.Subgrade bearing capacity is usually unable to meet the requirements and need to be strengthened.A series of finite element models such as wheel-track contact model,track model and roadbed model are established in this thesis.The analysis of rail strength,track structure strength and sleeper bending moment and so on is carried out.And a finite element static analysis of heavy haul railway of 40 t axle load has been completed.The results show that the surface stress of the subgrade will be 0.17 MPa,larger than the subgrade bearing capacity of 0.13 MPa,under the condition of the 40 t axle train with a speed of not more than 120 km/h in the Datong-Qinhuangdao line,thus subgrade needs to be intensified to meet the requirements;Optimal rail bottom slope depend on the particular wheel-rail contact face matching;Widening or lengthening type III sleeper can effectively enhance its carrying capacity,taking into account the boundaries of the track and other factors,the widening measures should be given priority in the design of 40 t axle load heavy haul railways.Combined with the traditional vehicle-track coupling dynamics and the latest explicit finite element method,the dynamic response of wheel force,fastener force,and roadbed force with the excitations of the fifth-grade road spectrum,wheel abrasion,rail welded joint and rail corrugation is calculated,those frequency range from 0.25 Hz up to nearly 1000 Hz.The results show that the dynamic stiffness of the track is 165-300 MN/m at the maximum speed of 90 km / h when the 40 t axle heavy load train is running,and the dynamic coefficients of the wheel-rail interface,sleeper and roadbed are 1.95,2.25 and 1.7.In order to reduce the rail wear in curved section of heavy haul railway running 40 t axle-load,the vehicle-track coupling dynamics model is used to analyze the response of the vehicle at different speeds.The analysis shows that setting the owe-ultrahigh of about-10% is advantageous to reduce the rail wear in the curved section,especially when the radius is less than 600 m. |
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