Vacuum consolidation theory of dredged slurry considering nonlinear clogging behaviors

Abstract

Clogging in the prefabricated vertical drains (PVDs) and soils is an inherent feature associated with vacuum treatment of slurry ground. The clogging column is characterized by nonlinear growth of volume over time and nonlinear permeability distribution along the radial direction. This study aims to develop a drain-well consolidation model for vacuum treatment of dredged slurry, with specific considerations of the nonlinear behaviors of the clogging column and PVD drainage capacity. The constitutive compression and permeation behaviors of the dredged slurry are described by extended power functions, which avoids the singularities associated with the conventional logarithmic constitutive equations when the effective consolidation stress approaches zero. Parametric studies were conducted to explore the consolidation effects while considering different combinations of parameters that govern the nonlinear behaviors of the clogging column and PVD-drainage capacity. The significance of considering the abovementioned nonlinear behaviors was demonstrated by comparing the field test results on a dredged slurry ground. Results indicate that clogging primarily affects consolidation by causing a nonlinear permeability distribution along the radial direction of the clogging column and nonlinear attenuation of PVD-drainage capacity.