Experimental and numerical study on collapse of quasi-two-dimensional bilayer granular column

Abstract

The collapse of granular columns has been widely investigated numerically and experimentally. However, a column consisting of single-sized particles is typically modeled; thus, the influence of the column composition needs to be analyzed. In this study, quasi-two-dimensional discrete element simulations and experimental tests were performed to assess the collapse of two-layered granular columns with different particle sizes in each layer. The effects of the particle sequence, column aspect ratio (AR), percentage of basal particles (Hl/H0), and particle size ratio between large and small particles (dL/dS) were evaluated. The results showed that the small particles moved slower than the large particles. The movement of the large particles in the upper layer was restricted because of the slow response of the small particles in the lower layer. Furthermore, the normalized final height, normalized run-out distance, peak value of average velocity, normalized kinetic energy, and normalized potential energy were analyzed in detail.