Study on the mechanical behavior of sands using 3D discrete element method with realistic particle models
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RESEARCH PAPER
Study on the mechanical behavior of sands using 3D discrete element method with realistic particle models Wen-Jie Xu1 • Guang-Yu Liu1 • Han Yang2 Received: 31 October 2018 / Accepted: 3 May 2020 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Presented is a study on the geometrical characteristics of sand particles and the mechanical behavior of sand material under external loading. Based on computed tomography technique, a reconstruction method of granular particles was developed and used to build a database of 3D geometrical models for sand particles. The studied sand particles showed good regularities in morphological characteristics and thus were suitable to be used for the random generation of numerical samples. DEM tests using realistically shaped particles were proven to better simulate the mechanical behavior of the sample during elastoplastic loading stage, which was an issue for the simplified spherical particles. The generation, extension, and breakage of the force chains controlled the strain softening behavior of sands. Anisotropy analysis using the spherical harmonic series showed that the evolution of anisotropy directions and parameters corresponded well with the macroscopic mechanical behavior of the material. Pore volume computation based on Voronoi diagram was performed to illustrate the formation and evolution of localized shear zone. The mesoscopic analysis showed that particle shape significantly influences the mechanical behavior of sands and thus should be properly modeled in numerical simulations. Keywords 3D particle Direct shear test Discrete element method (DEM) Failure mechanism Granular material
1 Introduction As a common granular material in geotechnical engineering, many numerical and experimental investigations on sands have been conducted in the recent few decades. The multi-scale mechanical behavior of sands has proven to be a key factor in engineering designs of embankments, foundations, slopes, and other infrastructures. Many numerical methods have been developed and used to simulate granular materials, like sands, on constitutive level and in practical engineering problems. More and more researchers noticed that the geometric shape performed important influence on the mechanical behaviors of granular materials [34, 37]. Previously, the researchers were & Wen-Jie Xu [email protected] 1
State Key Laboratory of Hydroscience and Hydraulic Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China
2
Department of Civil and Environmental Engineering, University of California, Davis, CA 95616, USA
mainly focused on the 2D model of the particles based on 2D images [11]. In the past decades, with the development of the techniques, the 3D surface of the particles can easily be obtained by laser scanning [19] or computed tomography [10]. At the same time, a series of methods have been developed to constructed the 3D model of the particles, such as Four
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