Constraints equations establishment for calculation model of double-block ballastless track in high speed railway

In order to appropriately deal with connection problems in kinetics analysis such as shell-beam-bar, superposition plates, beam axis-spring, shell-spring, shell-solid connections in high speed railway's slab track, Timoshenko-type shell theory and direct introduction method were based for establishing multi-point constraint equations and calculation model of the composite slab track. In the composite structure, to counteract different type elements' attribution to the composite structure's total rigid matrix caused by the elements' offset connections, the multi-point constraint equations on the basis of both the linear hypothesis in shell theory and eccentricity relations among relative nodes pairs in the composite structure were introduced to equilibrium equation. Multi-point constraint equations of different type elements were constructed theoretically, and followed by which the dynamic FEM model of the high speed railway's slab track was thereby established. The reliability of the FEM model based on Timoshenko-type shell theory and direct introduction method is reliable by the comparison between numerical analysis and real measured results, and meanwhile the model produces good connections among different layers of the structure, eliminating irrational additional stress generated in conventional methods.