Evolution of Fabric Due to Susceptibility of Fine Particles in Internally Unstable Gap-Graded Soils

Abstract Mechanical behavior of gap-graded soils prone to suffusion is heavily influenced by soil fabric, which undergoes readjustment in particles, interparticle contacts, and the pore network. The present study investigates the impact of some critical controlling parameters such as gap ratio, fine content, and relative density (𝐷 𝑅 ) on gap-graded granular fabric under isotropic compression stress conditions. An approach utilizing the Discrete Element Method to generate samples with a target-𝐷 𝑅 was employed. The variation in fabric indicators, such as the stress reduction factor (α), coordination number ( Z avg ), and contact distributions, including strong contact networks, across different percentages of fine particles, were used to illustrate the influence of fines on the soil stress matrix. Results indicate that soil packing with fine content of 20% ⩽ 𝑓 𝑐 < 35%, along with a gap ratio of 5, is in the transitional zone, initially unstable but becoming internally stable as 𝐷 𝑅 increases.