Calculation of reasonable-longitudinal-continuous length for bed plate of CRTSⅢ slab ballastless track

According to the design scheme of CRTSⅢ slab ballastless track on subgrade, the nonlinear interaction between multilayer structures was considered, and the spatial coupled models of track structure with different longitudinal-continuous lengths of bed plate were established based on finite element method.The lateral stability of track structure and the stresses and deformations of slab, self-compacting concrete layer and bed plate under the temperature load were computed, and the reasonable-longitudinal-continuous length of bed plate was analyzed.Analysis result shows that the lateral stability of slab track is satisfied when the continuous length of bed plate is greater than or equal to the connected length of 2 track slabs.Under the condition of temperature increasing 45 ℃, when the length of bed plate increases, the changes of stress and moment in track slab are not obvious, while the longitudinal displacement linearly increases, and the maximum increasing value is about 58%.For the self-compacting concrete layer, the changes of stress and deformation are more obvious than the values of track slab, and the maximum value of tensile stress is 0.949 MPa.Under the condition of temperaturedecreasing 40 ℃, the influence of continuous length on the bed plate stress is obvious.When the continuous length of bed plate reaches the connected length of 5 track slabs, the longitudinal tensile stress of bed plate increases to 2.67 MPa, which is close to the allowable limit of concrete tensile strength.In summary, based on taking into the factors of lateral stability and structural strength, the reasonable-longitudinal-continuous length of bed plate should be the connected length of 2-5 track slabs.