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.

Study of the Nonuniform Consolidation Characteristics of Soft Soils Using a Novel Model

“…As consolidation proceeds, the nonuniformity dynamically changes, and when the time is sufficiently long, the soil nonuniformity tends to be uniform (i.e., t = t ∞ ). On the basis of the effective stress principle, the excess pore water pressure of soft soil at any location continues to dissipate under ideal conditions and infinite consolidation time [3,9,14]. Therefore, as shown in Figure 2, the variation in permeability coefficients in the disturbed and undisturbed zones throughout consolidation can be simply divided into three states.…”

“…Numerous studies have found that the process of vertical drain installation forms a smear layer by squeezing the soil around the vertical drain [8][9][10]. According to the characteristics of the process of vertical drain installation, the layered expression centered on the vertical drain was the basic idea for building the vertical drain consolidation model [3].…”

Taş Kolon Tasarım Parametrelerinin Konsolidasyona Etkisinin Araştırılması

“…Tıklanmış kolon malzemesinin özellikleri kolon iskeletine giren kil miktarına bağlıdır. Kil zeminin kolon boşluklarını doldurması kolonun permeabilitesini azaltacaktır [20]. Kolon permeabilitesinin kolon imalatından doğrudan etkilendiği düşünülürse, kolon imalatı sırasında kolon permeabilitesini azaltabilecek etkilere dikkat etmek gereklidir.…”

Consolidation Analysis of Soft Ground Improved by Stone Columns Incorporating Foundation Stiffness

“…Finally, a governing equation specifying the variable, � , can be obtained, and the details of its derivation are given in Appendix II extending the past procedures (Lu et 8 al., 2010;Tai et al, 2017). 9…”