Effect of fines content on onset of internal instability and suffusion of sand mixtures

Prasomsri, J., Shire, T. and Takahashi, A. (2021) Effect of fines content on onset of internal instability and suffusion of sand mixtures. Géotechnique Letters, 11(3), pp. 1-6. (doi: 10.1680/jgele.20.00089)

Abstract

Internal instability or suffusion is one of the mechanisms of internal erosion in cohesionless soils, which is described by the loss of integrity of soil by seepage flow and is associated with the migration of finer particles. The contribution of the non-plastic finer fraction in a material is a key factor governing internal instability susceptibility. This study presents the experimental investigation of the influence of the fines content on the onset of internal instability of gap-graded sands using a pressure-controlled triaxial erosion device. The results indicate that the finer fraction in the soil has a significant influence on the hydraulic gradient at the onset of erosion. The underfilled soil with fines content less than 30% is vulnerable to suffusion at a relatively small hydraulic gradient. The transitional soil, whose fines content is between 30 and 35%, also exhibits suffusion, but the erosion onset hydraulic gradient significantly increases with increasing fines content. The overfilled soil with fines content larger than 35% exhibits suffosion or internal stability at a larger hydraulic gradient. The results also highlight the necessity of the multiple indices, such as mass loss, volumetric change and change in permeability, in evaluating the onset of various instability phenomena.

• Item Type: Articles
• Additional Information: The first author would like to acknowledge the scholarship support of the Japanese Government (Monbukagakusho: MEXT). This work was partially supported by JSPS KAKENHI Grant No. 19H02232.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Shire, Dr Thomas
• Authors: Prasomsri, J., Shire, T., and Takahashi, A.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Géotechnique Letters
• Publisher: ICE Publishing
• ISSN: 2045-2543
• ISSN (Online): 2045-2543
• Published Online: 16 July 2021
• Copyright Holders: Copyright © 2021 ICE Publishing
• First Published: First published in Géotechnique Letters 11(3): 1-6
• Publisher Policy: Reproduced in accordance with the publisher copyright policy