Experimental Investigations Of Mechanical Behavior and Deformation Characteristics of Silt Sugrade Reinforced by Wicking Geotextile

Abstract

Silt has traditionally been used as a subgrade filling material because of its abundant local supply. However, its moisture-sensitive shear strength and poor drainage properties often lead to water retention, settlement, and mud pumping in railway subgrades. Wicking geotextile, which combine drainage and reinforcement functions, have gained attention for improving subgrade strength. Despite proven efficacy, the influence of reinforcement parameters (i.g. compaction degree, reinforcement layer numbers, placement position, and specimen size) on the deformation characteristics of silt reinforced by wicking geotextile have not yet been fully understood, which limits the in-situ applications of the wicking geotextile soil treatment technology. In this study, unconfined compressive strength (UCS) and one-dimensional consolidation (ODC) tests were conducted on reinforced silt under varying compaction degrees, reinforcement configurations, and specimen dimensions. The results demonstrate that wicking geotextile significantly improved soil strength, particularly at lower compaction degrees, by inhibiting shear band formation. Although higher compaction alone raised strength, adding multiple layers of geotextile was more effective overall. The most pronounced reinforcement benefit was achieved by installing the geotextile at the specimen’s midpoint and spacing multiple layers uniformly. In contrast, specimens with a 1:2 diameter-to-height ratio exhibited poor stability and brittle failure. ODC tests revealed that reinforced silt undergone a more substantial reduction in void ratio, attributable to improved drainage and stress redistribution. These findings suggest that wicking geotextile can be strategically deployed to optimize silt strength and deformation controlling, offering a sustainable alternative measures to reinforce the railway subgrades.

Keywords: Silt subgrade, Railway, wicking geotextile, reinforcement parameters, unconfined compressive strength, one-dimensional consolidation