A nonlinear analytical model for consolidated geotextile-encased sand columns

Abstract

A nonlinear model for consolidated geotextile-encased sand columns (GESACs) was formulated. The model is based on a power law and predicts the stress-strain curve of a consolidated GESAC based on the superposition rule, wherein the stress-strain curve of the unconsolidated GESAC is superposed by the stress-strain curve of the soil alone in a consolidated triaxial test. A uniaxial compression test was conducted to study the failure mechanism of the GESAC. In addition, unconsolidated and consolidated triaxial tests on loose GESACs were conducted to investigate the effect of initial stresses on the shear behavior of GESACs. To further investigate the interaction between the soil and geotextile, and to assess the GESAC model, finite-element simulations were conducted. The results showed that internal lateral stresses developed in the GESAC due to the confining effect of the geotextile, which increased the circumferential tension force on the geotextile while the p-q path of the GESAC approached the critical state line and followed the line when the shear strength of the soil was mobilized. The model was verified based on data on dense consolidated GESACs found in the literature and the measured and predicted results showed good agreement.