Interaction Between Layered Saturated Soft Rock–Soil Mass and Pile Groups Considering Free‐Standing Length and Rock‐Socketed Depth

ABSTRACT This paper investigates the interaction between layered saturated soft rock–soil mass and pile groups considering free‐standing length and rock‐socketed depth. The modeling of the identical pile is on the basis of one‐dimensional compression bar with a three‐node bar element. The global force balance equation for the pile group is then derived using the finite element method (FEM). Taking the existence of free‐standing length of the single pile into account, the rock–soil mass stiffness matrix equation for a rock‐socketed single pile is expanded, and the global rock–soil mass stiffness matrix equation for the pile group is further derived on the basis of the boundary element method (BEM). Referring to the coupled FEM‐BEM, the solution for the free‐standing rock‐socketed pile group is further achieved by combining the conditions of force equilibrium and displacement coordination for the rigid cap. The correctness of the theory and method in this study is confirmed by validating with the existing solutions and ABAQUS. Further analyses are given to investigate the impact of key factors on the response of a free‐standing rock‐socketed pile group in the layered saturated soft rock–soil mass.