Analytical solution for axisymmetric consolidation of unsaturated composite foundation incorporating permeable columns and impermeable columns

Abstract

AbstractComposite foundation is a widely used foundation treatment technology in geotechnical engineering. This study are derived governing equations to axisymmetric consolidation of unsaturated composite foundation (USCF) incorporating permeable columns and impermeable columns under instantaneous loading, and obtained the final solutions of excess pore pressures (EPPs) by using mathematical methods such as the variable separation, decoupling, finite Hankel transform and its inverse transform. The analytical solution obtained under free strain conditions is more general and representative, as it can be readily degraded to solutions for a variety of consolidation models and the EPPs can be conveniently calculated at any point in the calculation cell. Through degrading proposed solutions to the special case to verify their correctness, the comparative results were found well‐matched to the existing literature solutions. The effect of various parameters on the consolidation performance of USCF was analyzed, where the studied parameters include the compression modulus of columns, radius ratio for permeable columns, and the number of impermeable columns. The results show that increasing the compression modulus and area replacement rates of columns can accelerate consolidation and reduce settlement, and the latter is more effective. Compared to reinforced composite foundations with only a single form of the permeable or impermeable column, the combination of permeable and impermeable columns can significantly shorten the consolidation time and enhance the bearing capacity of the unsaturated ground.