Analysis of flexible raft resting on soft soil improved by granular piles considering soil shear interaction

This paper presents a method for nonlinear analysis of flexible raft foundation resting on a granular layer over soft soil improved by granular piles. The raft is idealized as a thin rectangular plate. The granular layer beneath the raft is idealized as incompressible shear layer. The improved ground is represented schematically as a system of elementary columns (soft and stiff springs) mutually interacting because of internal friction and/or adhesion. The accuracy of the present method is validated by comparing its results with the results of other existing analysis methods, field measurements and results of the PLAXIS 3D program and shown to be valid. A parametric study is performed to investigate the effect of various parameters on the behavior of raft resting on granular layer over soft soil improved by granular piles. It is observed that neglecting the soil shear interaction in the analysis is highly affecting raft behavior.