关键词: 污染泥, 堆场处置, 自重固结, 污染物迁移, 数值解

Abstract: Based on the one-dimensional (1D) consolidation equation and advection-dispersion transport equation, this paper presents a solution for coupled self-weight consolidation and contaminant transport in confined disposal of contaminated sediments. The explicit finite difference method is used to solve the transport governing equation, whereas the analytical solution is used to solve the self-weight consolidation equation. In terms of contaminant transport, the proposed solution accounts for advection, diffusion, mechanical dispersion, linear and nonlinear equilibrium sorption, and porosity-dependent effective diffusion coefficient. The proposed numerical solution is compared with the CST1 numerical model to verify its correctness. Using the verified solution, a series of parametric study is conducted to investigate the effects of several important parameters (i.e., consolidation effect, soil compressibility and permeability, and initial contaminant distribution) on the contaminant transport process in the confined disposal of dredged contaminated sediment. The results indicate that the consolidation effect, soil compressibility, soil permeability and initial contaminant distribution have significant impacts on the contaminant transport process in confined disposal of contaminated sediments. Consolidation can greatly accelerate the contaminant transport rate. The contaminant cumulative mass outflow increases largely with increasing compressibility coefficient and permeability coefficient. The rate of contaminant transport is considerably affected by the initial contaminant distribution.

Key words: contaminated sediment, confined disposal, self-weight consolidation, contaminant transport, numerical solution