Research Of Prestressed Concrete Sleeper Optimization Design In Heavy Haul Railway

At present,concrete sleeper ? is widely used in Chinese heavy haul railway.In the heavy haul lines,concrete sleeper ? is damaged to some extent,such as sleeper crack,shoulder damaged,and ballast powdering seriously and so on.In order to better solve the problem of the damage of heavy haul railway sleeper in China,it is necessary to design special sleeper and support the use of heavy haul railway.The design of a 30 t axis heavy haul rail sleeper is presented.This kind of sleeper can reduce the damage of heavy haul railway sleepers and delay the powdering of the ballast,so that the heavy rail track structure is more perfect.First of all,according to the statistics of the national heavy-duty railway sleeper parameter data,the size range of the sleeper is initially determined.The limit state method is used to determine the section of prestressed concrete sleeper preliminarily.It mainly includes the calculation of the load effect(load moment and load stress)of the concrete sleeper and the resistance of the section(bearing moment and bearing stress).According to Provisional Specification for design of limit state method of railway track,the relevant provisions on the design method of prestressed concrete sleeper.And the partial coefficients of load effects under the ultimate limit state,normal serviceability limit state and fatigue limit state of the sleeper are determined to be 1.5,1.2 and 1.0 respectively.The load effect and section resistance of prestressed concrete sleepers with different heights,widths and lengths are studied.And the influence of the ratio of reinforcement and the tension of prestressed tendons on the resistance of sleeper is analyzed.According to the above results,the section size of sleeper is optimized.Secondly,the finite element model of prestressed concrete sleeper is established by using the finite element theory.Some factors which affect the stress state of concrete sleepers are studied,including the sleeper pillow gradient,the arrangement of prestressed tendons,and the supporting state of ballast bed and so on.Based on thestress state of concrete sleepers,the design parameters of the concrete sleeper are optimized.Finally,based on the finite element theory and the concrete damage theory,the finite element model of concrete sleeper static load crack resistance test is established.The static load and cracking moment of the design sleeper are studied and compared with the crack resistance of concrete sleeper ?.The section of designed sleeper is optimized again.According to the results of theoretical calculation and finite element numerical calculation,the length of the sleeper is recommended to take 2 600 mm,the width of the sleeper is recommended to take 350~450 mm,the height of the sleeper is recommended to take 190~210 mm and the sleeper pillow gradient is recommended to take 10%.And thus the six kinds of the section of the 30 t axis heavy haul rail sleeper are initially determined.Through the analysis of the crack resistance performance of the sleeper and the static load crack resistance of the concrete sleeper,the final design section of the concrete sleeper is identified as the 5th sleeper section.The reinforcement form of the design sleeper is arranged in double rows.Compared the crack resistance of this concrete sleeper with the traditional sleeper,the crack resistance of the rail is increased by 4.7%,the crack resistance of the sleeper increased by 22.7%,and the quality of sleeper is increased by 25.9%.