DEM simulation on the one-dimensional compression behavior of various shaped crushable granular materials
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ORIGINAL PAPER
DEM simulation on the one-dimensional compression behavior of various shaped crushable granular materials Takao Ueda · Takashi Matsushima · Yasuo Yamada
Received: 1 October 2012 © Springer-Verlag Berlin Heidelberg 2013
Abstract In order to investigate the effects of particle shape on the compression behavior of granular materials, a series of simulations was conducted using a two-dimensional discrete element method employing moment springs. Fracturable granular assemblies were constructed from particles of the same shape and size. The range of possible particle shapes includes disk, ellipse and hexagon, with different aspect ratios. Simulations of single particle crushing tests on elliptical particles showed that crushing could be classified into three types: cleavage destruction, bending fracture and edge abrasion, depending on the manner of compression. A series of simulations of one-dimensional compression tests was then conducted on six types of crushable particle assemblies; the three types of crushing mentioned above were also observed, but their rates of occurrence depended on the particle shape. Cleavage destruction was mainly observed with circular and elliptical particles; bending fracture was observed only with elongated particles; edge abrasion was frequently observed with angular particles. Despite the difference in crushing type, all samples, when subjected to intense compression, converged to a critical grading with unique void ratio, grain size distribution and aspect ratio, with a similar distribution of number of contact points. Keywords Grain crushing · Grain shape · Critical grading · Discrete element method
T. Ueda (B) · T. Matsushima · Y. Yamada University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577, Japan e-mail: [email protected] T. Matsushima e-mail: [email protected]
1 Introduction Natural soils mainly composed of fracturable materials such as volcanic products, remains of organisms, and weathered rock may frequently suffer from grain crushing. Even in ground made of stronger granular materials, grain crushing is also an important issue for various geotechnical engineering structures such as high rock-fill dams and end-bearing piles, where soil is subjected to high pressure. Grading change due to grain crushing necessarily alters the compressibility of the granular material, which may be a crucial factor in geotechnical design. Since the K 0 -condition (zero lateral strain condition) is typical in the compression of subsoil, it is important to understand the effects of grain crushing on grading change under one-dimensional compression. Terzaghi and Peck [1] referred to the volume change of sands due to the grain crushing for the first time. Roberts and De Souza [2] found that intensive grain crushing occurs around the yield point; Hagerty et al. [3] examined the effect of various parameters such as initial void ratio, median grain size, particle shape and initial moduli, on grain crushing; Lade et al. [4] showed that the degree of grain crushing is cor
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