Janssen effect and the stability of quasi 2-D sandpiles

英文摘要：

We present the results of three dimensional molecular dynamics study of global normal stresses in quasi two dimensional sandpiles formed by pouring mono dispersed cohesionless spherical grains into a vertical granular Hele-Shaw cell. We observe Janssen effect which is the phenomenon of pressure saturation at the bottom of the container. Simulation of cells with different thicknesses shows that the Janssen coefficient $κ$ is a function of the cell thickness. Dependence of global normal stresses as well as $κ$ on the friction coefficients between the grains ($μ_p$) and with walls ($μ_w$) are also studied. The results show that in the range of our simulations $κ$ usually increases with wall-grain friction coefficient. Meanwhile by increasing $μ_p$ while the other system parameters are fixed, we witness a gradual increase in $κ$ to a parameter dependent maximal value.