A Study on Internal Erosion of Low-Plasticity Silty Sand

Abstract

Internal erosion phenomenon of low plasticity silty sand causing by migrant of fines content within soil matrix is of great interest to engineers. A novel direct shear device was developed to enable controlled seepage flows to be introduced during testing. In this study, this new developed seepage flow direct shear test device was used to investigate the effects of internal erosion to non-plastic silty sand prior to shearing. Specimens prepared with different fines contents and relative densities were tested to examine the influences of fines and density state to planar shear strength of non-plastic silty sand after experiencing internal erosion.

The results revealed that coarse particles existing in the test specimens still dominate the behavior of soil. Hence, when all soil specimens had similar void ratios, the strength of the eroded soil is greater than that of the uneroded soil ones. Moreover, fines contents had noticeable influence on soil behaviors, regardless of whether an internal erosion process was applied to the samples. Results of presented study is hoped to improve engineers’ understandings in engineering behavior of low plasticity silty sand.