Numerical modeling of the geotextile positioning angle in the base and Subbase layer of the road pavement

Geotextile is a useful member of the geosynthetics family, characterized by high tension resistance, good filtration, and flexibility. One of its main applications is as a separator and border creator between base and subbase materials, preventing the entrance of aggregates from other layers and providing good filtering at the border of the base and subbase layer. Designing and constructing embankments on loose subgrades is a critical issue in geotechnics, given the high compressibility and low shear strength of loose soils, leading to long-term deformation and embankment instability, which decreases the useful life of the structure. Various methods, including soil reinforcement, have been proposed to improve embankment stability. This paper aims to improve the reliability coefficient of embankments reinforced by geotextile at different angles and placed on soft soil using the finite element method and the PLAXIS software. The results show that changing the geotextile angle from 0 to 0.95 degrees in sandy soil causes a 53% decrease in the embankment's safety factor, whereas this change had little effect on clay soil, with a 2.9% decrease in the safety factor by increasing the geotextile angle from 0 to 2.01 degrees. Furthermore, increasing the resistance of geotextile by about 2.86 times increases the reliability factor by an average of 14.31% in sandy soil and 2.125% in clay soil. This increase in geotextile resistance also raises the embankment's settlement limit until the moment before rupture by 60.64%.