Analysis On Influence Of Geometric Parameters And Operation Parameters Of Curve Line On Rail Wear Of Heavy Haul Railway

In recent years,the heavy-haul railway transportation has been favored by various countries because of its advantages such as low cost,heavy load and large volume.Vigorously developing heavy-haul railway transport can reduce operating costs,enhance transport capacity and improve transport efficiency.It is the main mode of coal and ore resources transport.With the increase of axle load and running speed,the impact of wheel and rail is intensified,which leads to the failure of rail,such as collapse and peeling.Another important factor that affects the rail failure of heavy-haul railway is rail wear,especially in the curve section of small radius rail wear more serious.Therefore,studying and solving the rail wear in the curve section of heavy-haul railway is an urgent problem to be solved in the safe operation of railway and to save the maintenance cost.Based on the theoretical support of vehicle-track coupling dynamics,wheel-rail multipoint contact and rail profile wear prediction method,this paper is based on reading a lot of reference materials.Firstly,UM software is used to establish the coupling model of heavy-haul railway vehicle-track.Secondly,the development law of rail wear in the curve section of heavy haul railway is deeply studied.Finally,the influence of curve radius,outer rail superelevation,rail bottom slope,running speed and truck axle load on rail wear is studied by rail profile wear prediction method.The main conclusions of this study are as follows:(1)As the radius of the curve increases,the side wear value of the outer rail and the wear power of the rail decrease significantly.It is suggested that the curve with a radius greater than800 m should be adopted in railway line selection design.With the increase of the outer rail elevation,the side wear value of the outer rail is the minimum at the equilibrium elevation.A proper setting of overelevation can effectively slow down the side wear of the outer rail.With the increase of the rail bottom slope,the cumulative wear depth of the outer rail side wear decreases first and then increases.When the rail bottom slope is 1:50 and 1:40,the cumulative wear depth of the outer rail side wear is small,and the appropriate rail bottom slope can slow down the external rail side wear.A smaller wheel/rail friction coefficient can reduce the rail wear.It is suggested to reduce the rail wear by timely grinding and oiling in the curve area with small radius.(2)With the increase of running speed,the cumulative wear depth and rail wear power of outer rail side wear increase significantly;The cumulative wear depth of vertical wear decreases first and then increases,and is the minimum at the equilibrium velocity,which indicates that the running speed of heavy load vehicles in the curve section can effectively reduce the rail wear when the speed is near the equilibrium velocity.With the increase of the axle load of freight cars,the cumulative depth of rail wear and the wear power of rail increase significantly,which indicates that the smaller axle load of freight cars can reduce the rail wear in the curve section,but it is difficult to reduce the rail wear by reducing the axle load due to the demand of heavy-load railway transportation.When the radius of the curve is 600 m,the outside rail side wear increases linearly with the increase of the number of mixed single cars passing through the curve.When the number of mixed single cars passing through the curve increases by 515463 times,the outside rail side wear value increases by 1mm.When the curve radius is 5000 m,the vertical wear of the outer rail also increases linearly with the increase of the number of mixed single cars passing through the curve.When the number of mixed single cars passing through the curve increases 467289 times,the vertical wear depth of the outer rail increases by 1mm.(3)The derailment coefficient and wheel weight reduction rate increase by 54% and 62%,respectively,with the increase of the outside rail side wear depth from 0mm to 6mm,and the operation safety of heavy-duty vehicles is significantly reduced.The wheel-rail vertical force and wheel-rail lateral force increase by 32% and 24%,respectively,and the wheel-rail dynamic interaction is slightly intensified.When the rail vertical wear depth increases from 0mm to 8mm,the derailment coefficient and wheel weight reduction rate increase by 56% and 89%,respectively.The rail vertical wear and external rail side wear have adverse effects on the safety of vehicle operation.Therefore,it is suggested that when the rail vertical wear and external rail side wear reach the limit,the rail should be polished and repaired in time or replaced with a new rail.