Kenichi Kawano

Numerical evaluation of internal erosion due to seepage flow

Started: October 2014
Supervisor: O'Sullivan, C.
Funding: Kajima Corporation (Japan)

Background

Filter materials are responsible for preventing internal erosion of the low permeability clay core in earth and rock-fill dams due to water seepage (Fell & Fry, 2007). Stability of these materials is a key concern for dam safety and sustainability. However, current design guidelines which adopt particle size distribution-based empirical relationships are not effective. In addition, despite many previous research studies, this failure mechanism is still poorly understood. Therefore, a fundamental study to develop understanding of the interaction between internal erosion and water seepage and constrictions will be performed using discrete element modelling. This research follows an earlier PhD thesis by Dr Tom Shire (Shire, 2014) and is in parallel with research using micro-Computed Tomography by Howard Taylor.

Research aims

This research will generate detailed information on the soil grain interactions, which cannot be measured in the laboratory. The aim of this study is to theoretically justify improvements to design and assessment guidelines with respect to suffusion or piping (Skempton & Brogan, 1994), taking into account influence of water flow. The DEM codes granular LAMMPS and PFC3D will be used.

References

• Fell, R. and Fry, J. J. (2007) Internal Erosion of Dams and Their Foundations, Taylor & Francis.
• Skempton, A. W. and Brogan, J. M. (1994) Experiments on piping in sandy gravels, Géotechnique, 44:3, pp. 449-460
• Shire, T. (2014) Micro-scale Modelling of Granular Filters, PhD thesis, Imperial College London

KENICHI KAWANO

PhD Candidate - Geotechnics 
Department of Civil & Environmental Engineering 
Imperial College London SW7 2AZ 
kenichi.kawano14@imperial.ac.uk