# Parametric Analysis for 3D Modeling of Consolidation-Induced Solute Transport Using OpenFOAM
## 1 Introduction  
During the consolidation process, the compression of the soil caused by external loads leads to the expulsion of pore water from the soil. This transient flow alters the structure of the pores and accelerates the transport of the solute. Therefore, it is crucial to consider coupled flow and deformation during consolidation when predicting solute transport in porous media. Most conventional solute transport models have been developed in porous media on the basis of various approaches with the advection-dispersion equation (ADE) [1; 2; 3; 4; 5]. Most of the earlier investigations often assumed that porous media were rigid, simplifying model development but overlooking soil deformation under load and consolidation. To address this, based on [PERSON]'s consolidation theory [6], [PERSON] [7] developed a solute transport model for small deformations. Later, [PERSON] and [PERSON] [8] further extended this theory to finite deformation scenarios, better capturing the complex relationship between soil deformation and solute transport under higher stress. [PERSON] and [PERSON] [9] analyzed the sensitivity of the model to boundary conditions one-dimensionally. The results show that in double drainage, consolidation affects the concentration profile but not the diffusion flux breakthrough. In the case of single drainage, consolidation has a significant impact on diffusion flux. [PERSON] [10] applied a one-dimensional consolidation algorithm and a two-dimensional solute transport algorithm to the coupled study of large strain consolidation and solute transport. Subsequent research expanded the solute transport models to multidimensional (2D or 3D) contexts [11; 12; 13]. Unlike one-dimensional models, multidimensional models capturespatial variations in both horizontal and vertical directions. [PERSON] and [PERSON] [14] used two-dimensional simulations to study contaminant transport in low-permeability porous media, while [PERSON] et al. [15] proposed a fully coupled three-dimensional hydro-mechanical-chemical (HMC) model to examine long-term solute migration, soil settlement, and pore water pressure in clay liners of landfills. Although these models significantly advanced simulations for saturated porous media, research shifted toward unsaturated systems as an understanding of unsaturated soil behavior improved. [PERSON] et al. [16], using [PERSON]'s consolidation theory [17], developed a one-dimensional model of small deformation for unsaturated porous media. Later, [PERSON] and [PERSON] [18] extended this model to 2D, allowing more precise simulations of the migration of solutes under unsaturated conditions. Despite advances in multidimensional consolidation-induced solute transport models, two significant gaps persist in current research. (1) First, studies on solute migration in unsaturated porous media under multidimensional conditions remain scarce. (2) Second, there is a notable lack of systematic sensitivity analysis for these models. Most existing research has concentrated on one-dimensional models, such as the parameter sensitivity analysis of a one-dimensional model carried out by [PERSON] and [PERSON] [19]. However, the absence of systematic sensitivity analysis for multidimensional models presents a critical issue that needs to be addressed. To fill in the research gaps above, this study aims to perform a comprehensive parameter sensitivity analysis of three-dimensional consolidation-induced solute transport models. By examining the influence of various parameters on the model predictions, this study will identify key factors that control the transport of the solute, offering theoretical insights for model optimization and practical application. The structure of this paper is as follows. Section 2 outlines the model, the governing equations, and the details of parameter selection. Section 3 assesses the accuracy of the model. Section 4 analyzes the impact of key parameters, including hydraulic conductivity, shear modulus, saturation, and Poisson ratio, on consolidation and solute transport.