Prise en compte de l'effet de la mise en place dans la modélisation numérique en 3D des colonnes ballastées dans l'argile molle

This paper presents a comparison of numerical modelling of the behaviour of reinforcements in the form of stone columns in very soft clay. The simulation is run using the software finite elements Plaxis, first in 2D, then in 3D. We are particularly interested in taking into account the application of the columns in modelling. Indeed, in practice, due to the expansion of the column, the ground in its close vicinity undergoes a lateral compaction and the horizontal stresses are increased. This lateral expansion of the stone column can be simulated numerically, with the values of volume deformation which correspond to those observed in practice, and which can be connected with those usually adopted for the ratio between the modulus of the column and the reinforced ground. It is shown that this expansion induces a significant decrease in the stone columns.