A major failure involving an exposed geotextile to contain dredged spoil

The development of facility for the export of LNG from coal seam gas required a major dredging program which, due to the proximity of the Great Barrier Reef, was subject to strict environmental conditions. Most of the dredged spoil was required to be disposed of into a purpose-built bunded disposal area, constructed over existing seabed shallows. The as constructed rock fill embankment unintentionally allowed significant leakage of dredged spoil through and along much of its perimeter, compromising the disposal area's effectiveness in meeting water quality requirements. The loss of the dredged material through the embankment was primarily attributed to the geotextile component of the wall not performing as anticipated by the design and construct alliance. The design and construction factors that lead to the failure are discussed. Guidance is provided so as to avoid similar designs from being implemented in the future.