Analytical solution for dynamic response of asphalt pavement with subgrade modulus varying with depth

The analytical solution for the dynamic response of asphalt pavement under falling weight deflectometer (FWD) load is obtained considering the viscoelasticity, transverse isotropy, interlayer contact and non-uniform distribution of subgrade modulus along depth. Firstly, based on the transversely isotropic axisymmetric dynamic equations, the constant coefficient ordinary differential equations for pavement structure and the variable coefficient ordinary differential equations for subgrade are established through the Hankel-Laplace transform. Then, combined with the Frobenius method and the stiffness matrix method, the analytical solution of dynamic response for the asphalt pavement is obtained, and the numerical program is also compiled. Then, the reliability of analytical solution is verified by comparison and the results of finite element method. Finally, the influences of interlayer condition, modulus ratio and distribution of subgrade modulus on the road deflection are analyzed. The results show that the interlayer contact and transverse isotropy in the pavement structure have a significant impact on the road deflection. The influences of the subgrade modulus distribution along depth also cannot be ignored. It is suggested that the above characteristics of pavement structure and subgrade should be fully considered in the FWD tests and mechanical analysis of the pavement.