September 4-7, 2017, Delft, the Netherlands - 25th Meeting of the European Working Group on Internal Erosion.
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Numerical investigation on the bimodal structure of particle
packings for a widely graded soil
P. Winkler
Bauhaus-Universität Weimar
M.R. Salehi Sadaghiani
Lahmeyer Hydroprojekt GmbH
Keywords: Internal Erosion, suffusion, granular media, widely graded soils, soils structure, skeleton, force network, Discrete Element Method.
The soils structure adapts to the applied stresses and affects directly the capability of a widely graded soil to transmit and distribute loads. The structure of the particles has a determining effect on the performance of soil under hydraulic and dynamic loads. This paper describes a method for the analysis of the particle contact force network specially for the particles which form the soil skeleton using a Discrete Element Modelling. For the simulations, a typical widely graded particle size distribution is used. A dense sphere packing with a specific particle size distribution of a widely graded soil is generated with the Modified Force Biased Algorithm. An approach to differentiate "coarse" and "fine" fractions of a widely graded soil is developed, which is consistent with the bimodal soil structure theory. Particle contacts and contact forces are analysed to evaluate the amount of potentially mobile particles which are prone to be transported through the soil skeleton. Also the homogeneity and isotropy of the simulated packings are assessed with different methods. In result a better prognosis of the vulnerability of widely graded soils to suffusion can be made. This approach provides a way to understand and give insight to the load bearing characteristic of a soil structure.
P. Winkler
Bauhaus-Universität Weimar
