Analysis of Axial Loading of Pile Groups in Multilayered Elastic Soil

This paper presents a semianalytical solution for axially loaded pile groups in multilayered, linear-elastic soil profiles. The piles in the group can have circular, square, or rectangular cross sections. The soil displacement surrounding a pile group is linked to the axial displacement experienced by each of the piles in the group. The method is based on assigning a displacement decay function to every pile in the group and then summing up for all piles in the group the product of the axial displacement of each pile and its associated decay function. The governing differential equations describing the response of the soil and piles are derived by applying the principle of virtual work and calculus of variations to the pile-soil system. The governing differential equations predicting the response of the piles are solved analytically using the method of eigenvalues and eigenvectors, whereas the differential equations describing the soil decay functions are solved numerically using the finite-difference method. The method produces displacement fields that are very close to those produced by the FEM but with less computational effort.