Performance of vertically loaded pile group embedded in layered transversely isotropic saturated viscoelastic soils

The flexibility matrices of layered transversely isotropic saturated viscoelastic soils are obtained by the extended precise integration method. The time-dependent solution to vertically loaded single pile in the soils is achieved through the coupling of finite element method (FEM) and boundary element method (BEM). The interactions among piles, as well as the compatibility condition of rigid cap on pile group, are considered to get the solution to the vertically loaded pile group in the soils. Several numerical examples are then presented to study the influences of soil and pile group properties, including viscoelasticity, transverse isotropy and stratification of soil, as well as length-diameter ratio and pile spacing. Finally, parametric analyses are performed to give the changing trend of displacement at the cap and the axial force of pile tops over time.