Bearing Capacity Design of Ram-Compacted Bearing Base Piling Foundations by Simple Numerical Cavity Expansion Approach

Abstract

The ram-compacted pile with bearing base (RBB) piling foundation has become one of the best solutions because it has low cost, high bearing capacity, and promising environmental benefits. However, its present design process relies heavily on some semiempirical calculations that typically lead to overconservative designs, meaning that costly pilot piling tests are commonly required before construction. This paper presents a novel finite-element modeling (FEM) cavity expansion method implemented in ABAQUS. First, the soil cavity limit pressure is obtained from FEM of a small spherical cavity that expands in a steady state, then the real horizontal diameter of the base is determined from the expansion modeling of a large cavity, and subsequently, the ultimate bearing capacity of RBB pile bearing bases is derived. The predictions obtained were validated by RBB pile static load test results from historic cases, showing that the FEM cavity expansion method is accurate and reliable. This study also explores the RBB piling mechanism from a cavity expansion point of view.