Dynamic responses of unsaturated ground with or without embankment under moving loads using 2.5D FEM with perfectly match layer

Abstract

ABSTRACT The dynamic responses of an unsaturated ground with or without an embankment are analysed using 2.5D finite element method (FEM) to investigate the effects of the soil saturation and the embankment. The Galerkin method is utilised to establish the weak form governing equations for an unsaturated poroviscoelastic medium in the framework of 2.5D FEM. To reduce the reflected waves from the truncated boundaries of the 2.5D FE model, the formulations of the perfectly match layer (PML) technique are coupled with the governing equations of the unsaturated medium. The unsaturated ground vibrations with an embankment under moving loads are analysed by the proposed 2.5D FE approach, to investigate the influences of an embankment on unsaturated ground vibrations. The results of this research found that the PML technique can effectively reduce the reflected waves in the 2.5D FE model of unsaturated grounds. The increased soil saturation would increase the ground vibration amplitude, as well as the pore water pressure. Constructing embankment on the unsaturated ground could reduce the vibrations amplitude under the moving load, however increase the ground vibrations at the foot of the embankment.