Influences of Different Boundary Conditions on Three-dimensional Structure of Ballastless Track-Subgrade under Exogenous Excitation

摘要

A semi-uniform viscoelastic boundary modified from the viscoelastic artificial boundary was proposed in this paper.The stiffness and damping coefficient equations of the three dimensional (3D)semi-uniform viscoelastic boundary were deduced.Three kinds of boundaries, i.e., semi-uniform viscoelastic boundary, fixed boundary and viscoelastic boundary were applied to analyze the 3D ballastless track-subgrade structure under the exogenous high-speed train loads using the finite element method (FEM) so as to verify the precision of the semi-uniform viscoelastic boundary.It was showed that the displacements under the semi-uniform viscoelastic boundary were very close to those of the viscoelastic boundary.Moreover, compared to the viscoelastic artificial boundary, it is much easier to apply the semi-uniform viscoelastic boundary using FEM because of its homogenization process.Therefore, the proposed semi-uniform viscoelastic boundary is very effective in investigating the dynamic response of the 3D track-subgrade structure under the exogenous excitations.