Evaluation of mechanical behaviour of gap-graded soils with particle property disparity

This study investigates the mechanical behavior of gap-graded soils using Discrete Element Method, considering varying particle properties between coarse and finer particles, particularly their particle Young's modulus. A comprehensive analysis was conducted for three distinct cases of gap-graded soils, with each case represents a unique combination of coarse and finer particle properties. The research found that differences in particle properties have a negligible effect on the post-consolidation void ratio, regardless of packing densities and stress levels. While the particle scale stress transmission within these gap-graded soils is moderately sensitive to particle property disparity, varying stress transmission can be observed under medium conditions. Notably, the small strain stiffness varies between these three cases. Finer particles with higher particle Young's modulus tend to exhibit greater small strain stiffness. Besides, a novel theoretical matrix method was proposed to investigate the relative contribution of coarse and finer particles to the small strain stiffness. This study then introduces a new state variable that considers the unique roles of coarse and finer particles in stress transmission and their particle property disparity. The effective performance of this state variable emphasizes the importance of considering these factors in the analysis and design of gap-graded soil structures.