Investigation of Long-Term Durability of Geotextile Material in Coastal Environments

Abstract

Geotextile tubes are widely used in coastal protection structures like revetments, breakwaters, and containment bunds. The geotextile material that makes up the tube is exposed to harsh environmental conditions, such as UV radiation and wave action throughout its design life. Thus, it is crucial to investigate and assess the long-term durability of geotextile materials used to form geotextile tubes used in coastal applications, especially since these critical structures are designed to last 50 years or more. A study was conducted on samples from a 6-year-old geotextile tube that was part of a containment bund on Singapore’s northeast coast. Samples were taken from multiple sections along the bund. At each section, samples were retrieved from three orientations: top facing, diagonal facing and side-corner facing of the tube. The physical and mechanical properties of these samples were tested and evaluated. Test results showed a retained tensile strength of 40-80% compared to virgin samples of the same grade. Additionally, a field trial was conducted to evaluate geotextile material durability under marine conditions along the Singapore coast. Multiple strips were installed at different water depths, and they will be retrieved at pre-determined period of exposure up to 2 years. Instruments like UV sensors, pore pressure transducers, and temperature sensors were also installed at each depth. Initial tensile tests results from samples that had been exposed up to 3, 6 and 12 months have been analysed and indicate that degradation, while minimal, varies with the depth of seawater submersion.