Hydraulic Conductivity of Binary Granular Systems: Does it Depend on Overall Regularity and Intergranular Porosity?

This study focuses on developing new expressions correlating hydraulic conductivity (K) in binary mixed soils with intergranular porosity (n_eq) and overall regularity (OR). Through a series of constant head hydraulic conductivity tests on three types of coarse-grained soils, varying proportions of low plastic river silt (S_p = 0% to 40%) were mixed with sand. Initially, sand-river silt binary assemblies were prepared with an initial relative index (I_d = 0.92). Analysis reveals significant influences of particle shape factors on hydraulic conductivity. The study elucidates the relevance of overall regularity (OR), shape factor (SF), and intergranular porosity (n_eq), introducing two novel parameters: [(OR)^0.5 × SF × n_eq] and [(1 + EG)/(SD)⁵ × (n_eq)^0.02]. The experimental findings highlight the robust predictive capability of these multi-variable expressions in systematically determining hydraulic conductivity. Such insights hold particular significance in geotechnical engineering, especially in understanding hydraulic responses within binary granular systems. Ultimately, this research contributes to a more profound comprehension of soil behavior and carries substantial practical implications for a wide array of engineering applications, facilitating more accurate predictions and design considerations in geotechnical projects.