(199e) Continuum Modeling and Discrete Element Simulations of Elastic-Quasi-Static Granular Flow in a Compressing Slot

The stresses generated by the horizontal compression of a vertical column of granular material is investigated. The column is open at the top so that the material is free to flow upward in the slot as it is compressed. Two continuum models of this problem are formulated: one based on Janssen's effect and the other using linear elasticity. The bulk parameters needed for these models are obtained from discrete element simulations of unidirectional compression and shear. Using these bulk parameters, we then compare the predictions of the continuum models to discrete element simulations of the compressing slot in order to verify that the physical mechanisms included in the continuum models are representative of the behavior of the granular material. Based on the outcome of this comparison, we can state that in a compressing column of granular material there is frictional flow of the material near the top of the column that results in an exponential increase in stress with depth. With further increases in depth, the stress saturates at a value predicted by a linear-elastic plane strain analysis. The predictions of the continuum model quantitatively reproduce the behavior seen in the simulations at various conditions confirming that these mechanisms are correct.