Dr. Jianfeng Wang

Abstract:

Internal erosion refers to the long-term and progressive process wherein seepage flow carries fine particles through the interstices between coarse particles, leaving empty voids within soil structure. This talk will introduce an experimental investigation into the progressive internal erosion behavior of two kinds of gap-graded granular soil, namely,  glass beads or Leighton Buzzard sand, during triaxial shearing using X-ray micro computed tomography (μCT). The experimental results reveal a wide range of particle- and pore-scale processes, behaviors and mechanisms that are responsible for the progressive internal erosion of the granular soils. The combination of experimental measurements and mCT image analysis reveal the evident impact of particle shape on internal erosion at both sample and pore scales. In contrast to spherical GB particles, the sample formed by irregular LBS particles exhibits higher shear strength, lower rate of fines erosion and different formation mechanisms of seepage channel. The above effects are found to be more attributed to the fine fraction rather than the coarse fraction of the gap-graded granular samples.