Effect of Particle Size Distribution on Soil-Steel Interface Shear Behavior

Abstract

The performance of rock-socketed concrete-filled steel tube piles is strongly dependent on the shear behavior of the interface between the steel and the surrounding soil. The effects of particle size distribution (PSD) on soil-steel interface shear behavior were investigated for a soil mixture composed of crushed sandstone and mudstone particles. Tests were conducted using a strain-controlled direct shearing apparatus. The results showed nonlinear relationships between the shear strain and the stress and revealed dilation of the specimens during the shearing process. The shear strength of the interface was found to be linearly related to the normal stress, obeying the Mohr-Coulomb criterion. Relationships between the shear strength parameters and PSDs were established. In combination with fractal theory, these were used to assess the variation of interface shear strength and the disintegration of particles in shear processes. With knowledge of the variation of the fractal dimensions of the PSD, an approach for evaluating the evolution of interface shear strength parameters was proposed based on the effect of PSD on shear behavior.