Soil Deformations Induced by Particle Removal under Complex Stress States

Abstract

Soil is composed of particles of various sizes. Once some particles are removed in a physical or chemical process, the particle contacts and soil microstructure will change, leading to irreversible soil deformations and changes in soil behavior. Understanding soil deformation characteristics caused by particle removal under realistic stress conditions is of great importance to the safety of earth structures. In this study, soil deformations induced by particle removal under complex stress states were investigated through a series of tests on a triaxial internal erosion test apparatus in which fine soil particles were removed through salt dissolution. These tests were performed under common realistic stress conditions: isotropic stress state, triaxial compression stress state, and triaxial extension stress state. Soil deformations, both local and global, were systematically measured using a photographic method. With a gradual loss of soil particles, both the axial and radial strains and the void ratio increased. Greater soil deformations developed under a larger shear stress ratio or a higher mean effective stress. The test results provide solid evidence for verifying numerical analyses of particulate materials.