Comparative study of performance of wicking and conventional railway geotextiles under the synergetic simulation of train loads and flooding

Abstract

Geotextiles are used within railways and highways to reduce settlement and improve drainage characteristics. However, the drainage performance of conventional geotextiles under unsaturated conditions can be limited due to capillary barrier effects. Therefore, more recently, wicking geotextiles consisting of woven fibers with deep groves have been developed to improve drainage performance. Despite these potential performance benefits and many related highway studies, there has been minimal study into the performance of wicking geotextiles for railways. Therefore, this study performs large-scale laboratory tests on railway ballast-subgrade materials under three conditions: non-stabilized (NSS), conventional geotextile stabilized (CGSS), and wicking geotextile stabilized (WGSS). Each test sample is subject to 600,000 cyclic loading cycles over 3 phases. The first phase is a stationary phase for consolidation, the second is to simulate loading directly after rainfall, and the third is to simulate loading after flooding. The results are analyzed and four conclusions are drawn: 1) both geotextile types prevent rainfall water from infiltrating into subgrade soils, however the wicking shows elevated performance, 2) the wicking geotextile produces capillary suction, which compared to the conventional geotextile, significantly delays infiltration and helps to reduce the moisture content in subgrade soils, 3) both geotextiles are capable of separation and filtration during rainfall and flooding simulation, however the wicking offers additional performance, 4) the deformation of both geotextiles is similar.