Use of Discrete Element Modelling to Assess the Internal Instability of Dam Filters

Shire, T. , O'Sullivan, C., Fannin, J. and Hanley, K.J. (2015) Use of Discrete Element Modelling to Assess the Internal Instability of Dam Filters. In: Proceedings of the XVI European Conference on Soil Mechanics and Geotechnical Engineering, ECSMGE 2015, Edinburgh International Conference Center, Edinburgh, UK, 13-17 Sept 2015, pp. 687-692. ISBN 9780727760678

Abstract

Internal stability describes the ability of the coarse fraction of a broadly or gap-graded cohesionless soil to prevent the erosion of the finer fraction under seepage. Two conditions for internal instability are that: (i) the fine particles carry a lower stress than the coarse particles (hydromechanical condition) and (ii) the fine particles should be small enough to pass through the void constrictions between the coarse particles (geometric condition). A complete understanding of each of these mechanisms requires consideration of the fundamental particle-scale mechanics. Discrete element modelling (DEM) uses simplified particle geometries and ideal contact models to enable systems of particles to be modelled. This paper discusses the use of DEM to look at both the hydromechanical and geometrical conditions. The discussion on the hydromechanical condition considers the hypothesis of Skempton and Brogan (1994), i.e. that a prerequisite for internal instability is a reduction of the effective stress in the finer fraction of the soil. Particular emphasis is placed on the influnce of relative density. To assess the geometric condition a constriction size distribution (CSD) must be derived from the DEM analysis results. The data support the use of characteristic particle diameters in filter design.

• Item Type: Conference Proceedings
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Shire, Dr Thomas
• Authors: Shire, T., O'Sullivan, C., Fannin, J., and Hanley, K.J.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• ISBN: 9780727760678