Potential of Flocculant-Aided Soil Slurry Dewatering in Land Reclamation: Laboratory Investigations

When soil slurry is used as a fill material in land reclamation projects, vacuum preloading or geotextile tube systems are often adopted for the dewatering treatment in a large scale. However, these two methods often suffer from clogging problems and impede further dewatering treatment. In this study, we test the potential of using flocculants to enhance the dewatering efficiency in a vacuum preloading model test and a geotextile tube model test. Experimental results show that, by adding a flocculant into soil slurry, the dewatering efficiency in terms of drainage volumes and rates is significantly improved as compared to that in pure soil slurry. The amounts of drainage water in the tests with flocculant addition are about 20% and 100% more than those in pure slurry tests in the vacuum preloading and geotextile tube model tests, respectively. The underlying reason could be the flocculation effect that prevents the movement of small soil grains and the formation of impermeable layers on the filters.