Multi-fractal characteristics of particle size distribution of granular backfilling materials under different loads

Abstract

Abstract This study is focused on the inhomogeneity and local heterogeneity of the particle size distributions (PSD) of granular backfilling materials (eolian sands and loess) from western mines of China under overburden strata loads. The multi-fractal spectrum and variations in corresponding parameters of PSD of granular backfilling materials were obtained under different loads using a laser particle size analyzer and an environmental scanning electron microscope (ESEM). The results indicated that the load had negligible effects on the multi-fractal characteristics of PSD of eolian sand. There were no significant variations in the capacity dimension D(0), the information entropy dimension D(1) and the bandwidth of the multi-fractal spectra (Δα) as a function of the load. In contrast, the load significantly affected the multi-fractal characteristics of the PSD of loess, and D(0), D(1) and Δα increased and then decreased (maximized at 2 MPa) as the load increased. Furthermore, there was a correlation between structural morphology parameters and multi-fractal parameters in the particle breakage process, which demonstrated that D(0), D(1) and Δα of PSD of granular backfilling materials could effectively reflect the particle breakage and the change of structural morphology parameters of backfilling materials under different loads.