Study On Calculation Method Of Stress And Defomation Of Layered System Of Subgrade Bed Structure In Heavy Haul Railway

High-speed passenger and freight overloading is two trends in today’s world of railway development.heavy rail transport capacity,economic and social benefits significantly,the development of railway heavy transport has become the direction of the world rail transport development.However,at present,the Heavy-Haul Railway Design Code(TB 10625-2017),the Design Code for Railway Subgrade(TB 10001-2005)and the Design Code for High Speed Railways(TB 10621-2014)are based on modulus and thickness equivalent assumptions.The dynamic stress and deformation at different depths of bedded bed structure are calculated by Boussinesq formula in the equivalence space after equivalent transformation.But the modulus-equivalent assumption can not well truly reflect the difference between the properties of different soil materials and the functions in the stress field distributions contributed by the ballast layer with high modulus,the bedding surface layer and the bedding bottom layer are not supported by rigorous theoretical basis.Based on this,in this paper,the transfer matrix method is proposed to solve the calculation method of the stress and deformation of the roadbed,and the supplementary method of the calculation method in the specification is improved.Based on the previous studies,this paper studies the following aspects:(1)Study on distribution law of heavy load train wheel on sleeper.The finite element method was used to establish the finite element model of the rail-track bed-foundation bed body-subgrade subgrade,and the distributions of wheel load on sleepers were calculated and analyzed under different axle weight and different subgrade surface fill conditions.(2)Study on Stress and Deformation Characteristics of Subgrade Bed Structure in Heavy Haul Railway Subgrade.Aiming at the foundation structure of heavy rail subgrade,the finite element model of rail-track bed-foundation bed body-subgrade soil was established.The stress distribution and the deformation law of the roadbed were calculated and analyzed under different axle weight and different subgrade surface fill conditions.Combined with the measured data,the validity and rationality of the results were verified.(3)Study on calculation method of stress and deformation of Four-layer subgrade bed structure system based on transfer matrix method.The results of finite element method of the upper part of sleeper were simplified to rectangular load.The transfer matrix calculation relational expression of the vertical stress and the vertical deformation of a four-layer layered system under rectangular loading was established.The vertical stress and vertical deformation at any depth of the bed structure under the rectangular load corner of each block are calculated.Finally,the vertical stress and vertical deformation at any depth of the bed structure under the upper load are obtained by superimposing the corner point method.Furthermore,the rationality of the method to solve the stress and deformation of the subgrade bed structure of the heavy railway was verified by comparing with the collected field data and the finite element calculation results,and further amended.