Abstract
Excess deposition of sediment aggravate tidal flat and sea bottom environment. To consider the resuspension of sediment, it is important to clarify the factor of critical shear strength change. In this study, we focused on liquid limit related with shear strength. Considering cohesion and repulsion force of sediment based on DLVO theory, ionic strength of pore water and adsorbed ion are important parameters determining electric double layer thickness and surface potential. It is expected that when the ionic strength becomes higher, the electric double layer becomes thinner and sediment tends to aggregate easily. In this study, to understand the factor of shear strength change, we discussed relationship among liquid limit, adsorbed cation of sediment, ion concentration of pore water, and amount of organic matter. The results revealed that amount of adsorbed ion have a little effect for liquid limit. Ionic strength have a strong correlation with liquid limit, when ionic strength become increase, liquid limit become decrease. In addition, it was found that adding 1 mL and 2 mL of 30% concentration hydrogen peroxide solution to 1 g dry weight of sediment, the liquid limit decreased 42% and 47%, respectively. These results mean amount of organic matter strongly influence on liquid limit.
