Dredged material disposal is an increasing problem facing today’s modern ports. Dredging is necessary to maintain channel depth for the safe passage of boats due to the natural process of sedimentation. Alternative disposal techniques are currently under investigation. This project examines the effect of desiccation on geotechnical properties of fine grained dredged material and the trafficability of the soil. A total of five samples from different locations around Brisbane are collected and tested.
Some of the physical and engineering properties, such as Atterberg limits, specific gravity, organic content, particle size distribution, void ratio and the effect of desiccation, are determined through laboratory testings.
Evaporation rate and the critical moisture content are calculated. The experimental desiccation rate is replicated using a mathematical model developed by Benson & Sill in 1991.
Soil strength profiles are obtained from a manual cone penetrometer for all 5 sites visited. Three cone penetrometer tests are performed under dry condition, and others are completed in wet weather. From the plot of cone loads versus depth, the thickness of the desiccated crust is determined, and the cone index calculated.