Analysis Of The Performance Of CRTS Ⅱ Slab Ballastless Track Structure Under Temperature

The change of temperature will cause stress and deformation in slab ballastless track structure. When the temperature stress reaches the tensile strength of concrete, it will cause the crack of slab and concrete supporting layer. And the slab warpage may lead to the disengaging of slab and cement emulsified asphalt mortar layer. In addition, the elastic layer will probably be worn under the repeated influence of the slab warpage. These dameges of the slab ballastless track structure will affect the function of its normal use. Therefore, temperature is attributed to the live load and taken into consideration as one of the main loads in the design of slab ballastless track structure.CRTS Ⅱ slab ballastless track is a type of slab ballastless track structure most widely used in our country at present. On the basis of the CRTS Ⅱ slab ballastless track on soil subgrade, and with the finite element analysis method, the mechanical behavior of continuous slab ballastless track under the affect of temperature is analysed and its influencing factors are discussed in this paper. The major work that has been completed is as follow:(1) According to the Fourier heat conduction equation, assuming that the temperature gradient exists only along the direction of thickness, heat transfer analysis of the CRTS Ⅱ slab ballastless track is accomplished and the temperature distribution of it is obtained.(2) On the basis of elastic mechanics and the temperature stress analysis method of cement concrete pavement, the temperature stress and deformation are analysed in combination with the characteristic of CRTS Ⅱ slab ballastless track, and the calculation method of the temperature stress and deformation in different situations of the slab are derived.(3) By means of finite element analytic software ABAQUS, the three-dimensional nonlinear finite element mechanical model of the CRTS Ⅱ slab ballastless track structure on soil subgrade is established. And simulation analysis of the structure is completed to get the mechanics response of CRTS Ⅱ slab ballastless track structure on soil subgrade under the affect of temperature load change in whole and temperature gradient load. Furthermore, the influencing factors of the mechanics response of the structure are studied respectively, which contain the magnitude of temperature gradient, vertical stiffness of the fastener and the longitudinal connection steel bars.(4) The main damage forms of CRTS Ⅱ slab ballastless track structure caused by temperature load are analysed, which contain cracking of concrete under tensile stress, the damage of cement emulsified asphalt mortar layer and separation of the different structural layer interface. And, the development of the three forms of damage is predicted simply.(5) According to the analysis results, several suggestions and measurements are proposed to control the adverse effect caused by temperature load on the structure of CRTS Ⅱ slab ballastless track.