Consolidation-Induced Solute Transport for Constant Rate of Strain. II: Comparison with Incremental Loading

Abstract

This paper presents a numerical investigation of one-dimensional large strain consolidation-induced solute transport for incremental loading (IL) and constant rate of strain (CRS) conditions. Solute transport accounts for advection, diffusion, dispersion, linear and nonlinear sorption, and equilibrium and nonequilibrium sorption, and is consistent with temporal and spatial variations of porosity and seepage velocity in the consolidating soil. Simulations were conducted using material properties for kaolinite clay and indicate that IL and CRS conditions produce significantly different responses during the course of consolidation, including applied stress, rate of settlement, excess pore pressure, and local strain. However, for a given set of initial and boundary conditions, final solute mass outflows and final solute concentration profiles for IL and CRS conditions were generally in close agreement, provided that total elapsed time and final average strain were matched for both loading procedures. Such agreement occurred for varying initial specimen height, initial contamination distribution, loading procedure, transport condition, and applied strain rate. Conversely, solute mass outflows were generally not in close agreement during the course of consolidation, with IL conditions producing higher mass outflow due to higher fluid outflow at the top boundary.