Permeability Characteristics and Mesoscopic Simulation of Clayey Sand

The permeability characteristics of clayey sand significantly impact the operation of projects such as groundwater recharge wells and borehole wall protection. This study quantifies the quantity of clay deposition in distinct particle size sand columns through a one-dimensional sand column recharge test. The evolution characteristics, including porosity, pore characteristics, and permeability coefficient, are investigated. A meso-permeability model for clayey sand is constructed using photo-grayscale processing, pore model extraction, and geometric modeling. The findings indicate that a reduction in sand particle size results in a notable decrease in the time required for the sand column to reach blockage. As the sand particle size decreases, the influence of clay content on permeability becomes increasingly evident. The particle size of sand has a pronounced impact on the porosity of samples with low clay content, whereas it exerts a negligible influence on the porosity of samples with high clay content. An increase in clay content is observed to enhance the cementation ability of the clay, particularly at the surface level. The proposed numerical model of pore and permeability effectively simulates the pore characteristics and permeability characteristics under varying particle sizes and clay contents at the mesoscale.