Modeling of uniformly loaded circular raft resting on stone column-improved ground

Abstract

In the present paper, a mechanical model has been developed to study the behavior of uniformly loaded circular raft resting on stone column-improved ground. The axi-symmetric condition was considered in the analysis. The raft was idealized by a circular plate. The soft foundation soil and granular fill were idealized as the spring-dashpot element and the Pasternak shear layer, respectively. The stone columns were modeled as stiff non-linear springs. To perform an axi-symmetric analysis, stone columns are converted into equivalent concentric rings with one stone column at the center. The finite difference method is used to solve the governing differential equations. The effect of different parameters on the behavior of the circular raft over stone column-reinforced ground was also studied. It was observed that the effect of the modular ratio on the rate of decrease of vertical settlement, radial and tangential moment and the rate of increase of shear force reduces sharply above the value of 40. The shear force developed at the edge of the stone column was critical when the spacing to diameter ratio was around 2.5.