Reclamation using waste sediment by sand capping technique

Abstract

Disposal of unwanted seabed sediment arising from dredging activities is an increasingly intractable problem. One solution is to use the sediment as fill material for land reclamation, as a replacement for sand, the traditional fill. As the water content of sediment is high, even a small fill will ensure rapid consolidation. The underlying philosophy is to place a layer of sand on top of the slurry to accelerate consolidation. This paper summarizes the research carried out in Singapore. A pilot test and a large-scale project will be described and the results from monitoring discussed. A physical framework will then be provided to explain the sand capping of the sediment, followed by the introduction of a simplified model to connect the two key aspects of the mechanics of sand capping, namely the accumulation of sand on the sediment and the way the slurry gained shear strength to resist this load. This simple model was able to produce results consistent with that observed in the field.