Dynamic responses of graded nonhomogeneous unsaturated soils under a strip load

Based on the three-phase porous media mixed theory, the dynamic governing equations of unsaturated soils is established and the dynamic response of graded nonhomogeneous unsaturated soils subjected to a strip load is studied. Combined with the reverberation-ray matrix method (RRMM) and the boundary condition, the calculation formula of the displacement, stress and pore pressure of graded nonhomogeneous unsaturated soils is derived. Assuming that the continuous variation of physical and mechanical properties of unsaturated soils along the thickness-coordinate by exponential law distribution, the numerical solution of the displacement, stress, and pore pressure then obtained by using numerical inverse Fourier transformation, and the influence of soil heterogeneity and saturation on the dynamic response of unsaturated soils is discussed. The results show that the displacement decreased with increasing gradient factor, and the stress first increased then decreased with the gradient factor increased, and the pore pressure first decreased then increased with increasing gradient factor. The displacement and pore pressure under different gradient factors all increase with increasing saturation.