Particle contact characteristics of coarse-grained soils under normal contact

Current research on coarse-grained soils focuses primarily on the physical and mechanical properties of particle aggregates; research on particle contact characteristics is rare. Furthermore, existing studies on particle contact characteristics tend to focus on artificial substitutes such as high-strength gypsum and on the bonding behaviour of ideal rigid particles. Systematic studies of the mechanical properties of contact between dispersed particles are even more rare. In this study, contact between actual particles (including granite, marble, limestone, slate and sandstone) is simplified to point–point contact and point–plane contact. Using the rock rheological testing system, a normal contact experiment involving coarse-grained soil particles was carried out for different contact forms, materials and particle sizes. This was done to study normal contact characteristics and obtain constitutive model parameters for the normal stiffness of the contact point. The parameters were then applied to a numerical analysis by using particle flow code in three dimensions through the FISH language, and the normal contact stiffness for particles was subsequently obtained.