Behavior of Foundation on End-bearing Stone Columns Group Reinforced Soil

Abstract

The prediction of the settlement of foundations on soil reinforced by a group of end-bearing stone columns was investigated. 3D numerical models with constant improvement area ratio are considered into two configurations. The first configuration consists of stone columns group located in regular triangular pattern. Whilst, an equivalent reinforcement by concentric crowns is used by the second configuration. Geotechnical parameters of the reinforced soil modeled by the Mohr Coulomb constitutive law are adopted from Tunisian case history. Numerical predictions of the settlement by the finite difference code FLAC 3D and analytical ones by Columns and COLANY software are compared. It has been verified that the settlement prediction by the unit cell model is underestimated in regard to predictions obtained by the 3D reinforced soil models. Elsewhere settlement predictions by the equivalent concentric crowns are close to those obtained by the corresponding models of stone columns group reinforcement. When the equivalent concentric crowns reinforcement is adopted the increase in contact area with the soft soil does not affect the settlement prediction when total adhesion is assumed along those interfaces. Using the FLAC 3D code, it is more suitable to handle the input data by the equivalent concentric crowns to perform the computations.