Modelling size effect on rock aggregates strength using a DEM bonded-cell model
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RESEARCH PAPER
Modelling size effect on rock aggregates strength using a DEM bonded-cell model Yoshiro Huillca1 • Matı´as Silva1 Gabriel Eduardo Villavicencio5
•
Carlos Ovalle2,3
•
Juan Carlos Quezada4
•
Sergio Carrasco1,2
•
Received: 6 January 2020 / Accepted: 3 August 2020 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Empirical evidence has shown that particle breakage affects the mechanical behaviour of granular materials. The source of this mechanism takes place at the particle scale, and the main consequence on the macromechanical behaviour is increasing compressibility. Due to the inverse correlation between particle size and particle crushing strength, coarse rockfill materials are particularly vulnerable to mechanical degradation due to particle breakage. However, such coarse materials do not fit in standard laboratory devices, and the alternative of large sample testing is usually unavailable or too expensive. Alternatively, recent works have proposed multi-scale approaches using the discrete element method (DEM) to carry out numerical testing of coarse crushable materials, although few studies have focused on size effects. This article presents the application of a DEM bonded-cell model to study particle size-strength correlation on angular rock aggregates. Each particle is modelled by a cluster of perfectly rigid polyhedral cells with Mohr–Coulomb contact law. Constant cell density within particles implies that the presence of potential fragmentation planes increases with size. Therefore, particle strength decreases with size. A comprehensive sensitivity analysis was carried out through 1477 particle crushing simulations in a given particle size. Based on published experimental data on calcareous rock aggregates, part of the simulations were used for calibration, and 97 additional simulations of a coarser size fraction were performed for validation. The results show a good agreement with the empirical data in terms of size effect and data scatter through Weibull statistics. Keywords Bonded-cell model Discrete element method Particle crushing Size effect Weibull distribution
1 Introduction
& Matı´as Silva [email protected] 1
Departamento de Obras Civiles, Universidad Te´cnica Federico Santa Marı´a, Av. Espan˜a 1680, Valparaiso, Chile
2
Department of Civil, Geological and Mining Engineering, Polytechnique Montre´al, Montreal, Canada
3
Research Institute of Mining and Environment (RIME UQAT-Polytechnique), Montreal, Canada
4
ICUBE, UMR 7357, CNRS, INSA de Strasbourg, Strasbourg, France
5
Grupo de Geotecnia, Escuela de Ingenierı´a en Construccio´n, Pontificia Universidad Cato´lica de Valparaı´so, Avenida Brasil 2147, Valparaiso, Chile
Particle breakage in granular materials generates degradation of the mechanical response. Namely, the reduction in particle size due to grain fragmentation results in increasing compressibility, as well as decreasing dilatancy and peak shear strength [6, 18, 31, 41, 47, 58]. Fra
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