Strength and Stiffness Evolution of Remolded Dredged Sediment Under Wetting–Drying Cycles and a Generalized Hyperbolic Constitutive Model

Wetting–dryingcycles change the strength and deformation of dredged sediment used as fill. Stiffness and strength may not change at the same rate, and how to model this difference is still unclear. Triaxial tests were conducted on remolded dredged sediment after different numbers of wetting–drying cycles to examine differences in strength and initial stiffness evolution and their constitutive representation. A generalized hyperbolic model with a shared shape parameter was developed. Its descriptive capability was assessed through joint calibration, baseline model comparisons, and holdout tests at intermediate cycle numbers. An illustrative slope sensitivity study was conducted under specified assumptions, after the Abaqus user material subroutine (UMAT) had been verified against the analytical triaxial response. Cohesion and the friction coefficient decreased with cycling, but the latter showed greater relative reductions and different stage-wise changes. The initial modulus decreased after the first cycle. Later changes differed with confining pressure, but these trends were based on single-specimen results and need to be confirmed by replicate tests. The model achieved a global R2 of 0.9675 and reduced the root-mean-square error by 17.3% relative to the classical hyperbolic model. However, the simplified stiffness history could not reproduce all subsequent modulus changes. Nonlinear slope displacements exceeded frozen-tangent results by 9–23% for the proposed formulation (7–20% with the exponential form). This trend persisted across parameter treatment schemes, but absolute displacements were sensitive to low-confining-pressure extrapolation and Poisson’s ratio. The study quantifies calculation deviations caused by constitutive simplifications and displacement sensitivity to supplementary assumptions, guiding further testing and validation.