Working mechanism of a new wicking geotextile in roadway applications: A numerical study

摘要

Woven geotextiles are often to be used in roadways for reinforcement purposes due to their higher tensile strengths. In the design of a woven geotextile for practical applications, the focus is mainly put on its reinforcing effect, while its hydraulic behaviors are not major design parameters and the influence of hydraulic properties on the reinforcing effect is often ignored. However, woven geotextiles are predominantly made of polypropylene and polyester, which are hydrophobic. This characteristic can result in a capillary break effect which it is equivalent to raise the ground water table to the location where the geotextile is installed. Numerous researchers have reported that the moisture storage from a capillary break effect can be detrimental to the long-term performance of a pavement structure. Until now, no method is available to effectively resolve this issue. Recently a new type of wicking geotextile is produced which has the capability to laterally drain excess water in a roadway under both saturated and unsaturated conditions. Several field applications demonstrated its potential in improving pavement performance. This paper attempted to investigate the working mechanism of the wicking geotextile through numerical studies and quantify the benefits of the wicking geotextile in term of drainage performance in a pavement structure. A numerical model was developed and validated using column test results from existing literature. After that the drainage performance of the wicking geotextile under different working conditions was simulated and evaluated.