EFFECT OF CONSTRUCTION SEQUENCE ON THE PERFORMANCE OF GEOTEXTILE TUBES IN A CONTAINMENT BUND

Geotextile tubes (geotubes) filled with lightly Cement-Mixed Soil (CMS) are used to construct a containment bund. The proposed containment bund was made of three layers of geotextile tubes, where each of the geotube was infilled to a height of 2m and stacked to form a 6m high containment bund in the shape of a triangular prism. Three geotubes were placed side by side to form the first layer of the containment bund. The shear strength development of the CMS of the first layer containment bund was evaluated using a modified mini Cone Penetration Test (CPT) after the infilling. The results suggested that the shear strength developed in the centre geotube is generally lower than the edge geotubes. It was hypothesised that the edge geotubes, which were installed before the centre geotube, hindered the dewatering action of the centre geotube during its infilling process. Hence, a study on a scaled-down version of the three geotubes arrangement was conducted in the field with instrumentation. The hypothesis mentioned above was examined through the changes in volume and strain mobilised in the geotextile of geotube, the dewatering rate, and the shear strength development of the CMS, pore pressure and total pressure changes during infilling and dewatering phase of the geotubes. The study showed that the construction sequence of the geotubes indeed affects the shear strength development of the CMS.