Experimental study on sediment clump

• Main Author: Yang, Yang
• Other Authors: Law Wing-Keung, Adrian
• Format: Final Year Project
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Civil engineering::Water resources
• Online Access: http://hdl.handle.net/10356/71385
• Institution: Nanyang Technological University

A group of dense particles released instantaneously into stagnant ambient water is generally studied as thermal-like formation, experiences the classical three regimes of transition, namely the acceleration, thermal and dispersive regimes (Wilkinson & Rahimipour 1992). However, Wen & Nacamuli (1996) observed a new phenomenon with the formation of sediment clump(s), which can be characterized by a fast-moving front core with sediments shedding into the wake. This behavior, also called the wake-like formation has potentially huge impacts to the environment if it is present during the sediment disposal operation, which is generally practiced during the dredging and land reclamation activities. The sediments shed into the wake are likely to be left suspended within the water column and susceptible to be washed away by the ambient currents. This reduces the efficiency of the operations and possibility of environmental contamination. While the sediment cloud with thermal-like formation has been researched extensively, information is lacking in the wake-like formation. Preliminary experimental study showed that the behavior of sediment clump has high variation between each replicate. Hence, it is necessary to produce enough data to determine reliable results that reflect the averaged behavior of the sediment clump under a single test condition. This study focused on the number of replicates ought to be conducted to collect enough data for representable results. A total of 300 replicates were performed with 100 replicates for three sets of test condition. The behavior of sediment clump was found to follow a probabilistic model and the disintegration depth of a sediment clump followed a one-sided bell-shaped curve. It was also observed that clump fragmentation would greatly affect the sediment clump behaviors.