Comparing the effect of particle size distribution on minimum dry density in laboratory deposition and DEM simulations

Earlier emax test data indicate that the grading entropy S (where S = S0+ΔS) and the minimum dry density Smin (where Smin=S0+ΔS) of granular materials, measured in the emax tests, exhibit an approximately linear relationship. Almost linear relationships also hold for the decomposed variables: between the base entropy S0 and the mean fraction density S0, and between the entropy increment ΔS and the density increment ΔS (see [1]). Now, with further analysis, the test data obtained from sand samples with optimal grain size distributions are evaluated separately for sample series in which the number of fractions N in the mixtures is fixed. We show that there is an approximately linear regression between ΔS and ΔS for every N, and its regression coefficient increases with N (for N=2,3,5). Further analysis concerns the largest value of the minimum dry density Smin and its location, and the largest value of the density increment ΔS. We also report on some related frictionless DEM simulations showing that when two monodisperse grain materials are mixed, the density increment ΔS changes similarly to the laboratory test results.