Vertical Dynamic Response of a Pile Embedded in Layered Transversely Isotropic Unsaturated Soils

This paper investigates the dynamic response of a pile embedded in layered transversely isotropic unsaturated soils subjected to a vertical external excitation. The quintessential Biot biphasic model for saturated media is replaced with a triphasic model for unsaturated media, which simulates more realistic terrestrial subsurface soil characteristics. With the aid of the boundary element method (BEM), the soil around the pile is divided into a series of elements and the Green's function is obtained by the extended precise integration method (EPIM), while the pile is modeled as a 1D bar based on the finite element method (FEM). Thereafter, the soil-pile interaction formulation is acquired and further solved by the coupling of the BEM-FEM. The correctness of the proposed theory is verified by a comparison example with the existing results. A series of parametric studies are further provided to discuss the influences of degree of saturation, pore size distribution, and air-entry pressure on the dynamic behavior of the pile.

Automated summary

This paper investigates the dynamic response of a pile embedded in layered transversely isotropic unsaturated soils subjected to a vertical external excitation. The triphasic model is used to simulate the unsaturated media more realistically, and the BEM-FEM coupling method is employed to obtain the soil-pile interaction formulation. The correctness of the proposed theory is verified, and further parametric studies are conducted to discuss the influences of various factors on the dynamic behavior of the pile.