Experimental simulation and mathematical modelling of clogging in stone column

Abstract

In this paper, time-dependent clogging is studied considering a unit cell consisting of a single stone column interacting with the surrounding soft clay. Clogging is assessed quantitatively and the corresponding void space of the column is determined using computed tomography. It is observed that the extent of clogging is substantial in the upper part of the column, but diminishes rapidly with depth. The soil properties in the clogged zone are determined indirectly through additional tests of clay–aggregates mixtures with various clay fractions. An equal strain consolidation model based on the principle of unit cell analysis is developed to capture both the initial and time-dependent clogging. The model accounts for a reduction in permeability and an increase in compressibility of the column. This current model, as expected, offers identical results to some previous studies if clogging is ignored, while the comparison with other selected models demonstrates the influence that clogging of the stone column can have on the consolidation of the surrounding soil. Furthermore, load–settlement predictions from the proposed “equal strain” model are also compared with the consolidation response of a previously developed “free strain” model.