Modeling the settling and consolidation of soft sediments
Type:
Presented during:
CEDA Dredging Days 2026
Authors:
I. Myouri, C. Smeenk, C. Chassagne, N. Hol and L. Pel
Abstract
Sediments are fine, sludgy materials composed of mineral particles mixed with varying amounts of organic matter. They commonly accumulate in aquatic environments such as rivers, lakes, and estuaries, forming soft deposits that must often be dredged for navigation purposes. With growing concerns over resource scarcity and environmental impact, these dredged sediments are also increasingly viewed as a sustainable alternative to natural sand in large-scale applications such as land reclamation. However, their reuse presents significant geotechnical challenges due to their high water content, organic fraction, and slow strength development. Sediments obtained through modern hydraulic dredging techniques are typically highly diluted suspensions, where fine particles are dispersed in water. In this early sedimentation phase, particle motion is governed by gravity and colloidal non-contact forces, while Brownian motion and osmotic pressure slow down settling. As particles accumulate and form a network of contacts, the material enters the consolidation phase, dominated by self-weight compression and contact forces. Owing to their low permeability and compressible organic content, this phase progresses very slowly. Furthermore, sediments can exhibit swelling and shrinkage, behaviors rarely observed in sands, further complicating their mechanical response. Despite many studies addressing individual mechanisms, a unified framework linking sedimentation, consolidation, and large-strain states remains absent. In this presentation, we introduce a comprehensive model capable of predicting sediment behavior from the dilute suspension stage to the saturated and unsaturated conditions of dense deposits. The model incorporates engineering optimization techniques-such as applied loading and enhanced drainage-to accelerate densification and achieve target strength. In addition, we present a range of model calibration methods, from simple empirical approaches to advanced techniques such as Nuclear Magnetic Resonance (NMR), highlighting their applicability and reliability. This unified framework advances understanding of fine, organic-rich sediments and promotes their safe, efficient, and sustainable reuse in land reclamation and geotechnical projects.