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Abstract The scale effect of density on the mechanical properties of coarse-grained dam materials is ignored in previous studies. On this basis,four scale methods are used to obtain the maximum dry density in laboratory according to the original average design gradation curve of rockfill in Shuangjiangkou earth-rockfill dam. Based on the design generatrix of the coarse-grained dam materials gradation—Talbot curve and fractal geometry theory,the mechanism of scale effect of density for coarse-grained dam materials is interpreted,which selects the Talbot formula index and the factor reflecting the particle shape and roughness as the fractal indices. The basis of quantitatively evaluating the effect of gradation on density is provided;and the shortcomings of fuzzy evaluation only using the non-uniformity coefficient and curvature coefficient is overcome. Combined the mixed scale method,the numerical tests on the maximum dry density is carried out by using the particle flow code in two dimensions(PFC2D);the law of scale effect on the relative density and porosity of coarse-grained materials is studied;and the microscopic mechanism causing the difference is analyzed.
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Received: 11 August 2010
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