424 / 2024-09-16 19:36:57

Influence of Biopolymer admixture on rheological behavior of cohesive sediment

Artificial cohesive sediment; Natural mud; Rheological properties; Yield stress; EPS content; Water content; Kaolin content

Session 17 - Advances in Coastal Hydrodynamics and Sediment Dynamics for a Sustainable Ocean

This study investigates the rheological properties of cohesive sediments, focusing on the significant role of organic matter and extracellular polymeric substances (EPS) in these properties. Given the challenges of collecting sufficient natural mud for physical model experiments, we aimed to develop EPS-containing artificial cohesive sediments as a viable alternative. Using a rotational rheometer, we conducted steady and oscillatory rheological tests on kaolin-quartz suspension samples with varying EPS content, alongside tests on natural mud from Zhoushan Island, China. Our findings revealed a two-step yielding process in EPS-free samples, with yield stress increasing as water content decreased or kaolin content increased. Notably, even 0.1% EPS markedly influenced rheological behavior, with yield stress showing a non-monotonic response to EPS content. Additionally, the effectiveness of EPS was affected by water and kaolin content, indicating that higher water content and lower clay content can limit EPS impact. This research quantitatively explores the relationship between EPS and yield stress in artificial cohesive sediments, confirming the feasibility of using these sediments in physical model experiments as substitutes for natural mud, despite the complexities involved.