A Double-layered Model for Highway Subgrade and its Dynamic Response due to Traffic Loads

In this paper, a 3D double-layered model is introduced to simulate the highway subgrade after ground improvement and thus analytical solutions for the dynamic response of the model subjected to a constant rectangular moving load are derived. Based on elastodynamics and Biot's poro-elastic theory, the general solutions are obtained using the Helmholtz decomposition method and the Fourier transformation. The boundary value problem is formulated in the transformed domain and its final integral solutions are presented in time-space domain. Numerical calculations show that the analytical solutions can take into account some design parameters of ground improvement, which include load speed, permeability of the porous medium, stiffness and thickness of the reinforced layer. The results in this paper may be used as a reference to optimize the ground improvement scheme.