Geotextile tubes as containment dykes and breakwater structures

Containment dykes and breakwater structures are essential structures that are required prior to the start of land reclamation works. Its function is to act as retaining structure and to protect reclamation areas from sea-wave erosion. In the vicinity of Ancol, located in the Northern area of Jakarta, the seabed consists of a thick soft soil layer, the bearing capacity is very low. This condition becomes one of the greatest challenges to construct a strong and durable containment dyke and breakwater structure. Other challenges to be considered are the sea waves, sea current, and extreme tidal conditions. To meet with these challenges, geotextile tubes were selected to serve as a containment dyke, as well as forming the core of the breakwater with A-Jack concrete blocks implemented as the armor layer. The advantage of using geotextile tube as a breakwater’s core in contrast to the conventional method of using a rubble mound, is that it reduces the construction time whilst offering significant cost savings. When designing geotextile tubes as containment dykes and breakwaters, the data that needs to be addressed include the settlement analysis, especially for soft seabed soil, and sea depth, including the wave’s height. Based on this data, a proper dimension, fabric type and strength of geotextile tube can be determined. The geotextile fabric used should have sufficient high-tensile strength with low elongation to withstand the water pressure during filling process. The design result of geotextile tube must meet the internal and external stability criteria, and required durability.