Memory of fabric anisotropy in the static packing of granular materials

We look into the influence of the anisotropic distribution of fabric and force network on the angle of repose, which is technically accomplished by fabricating several trap doors underneath a mother granular heap with the angle of repose alpha, to generate two child heaps with the angles of repose beta (for the left child heap) and gamma (for the right child heap) through the particle removal. The results indicate that with the deposition plane orientation angle theta varying from 0 degrees to 90 degrees, beta experiences a local minimum value at theta = 30 degrees similar to 45 degrees, and. takes a local maximum value at theta = 45 degrees similar to 60 degrees. As the trap door position shifts towards the free surface of mother heap, beta increases first and then decreases in the experiments, and gamma rises monotonically, with the existence of relation gamma > beta approximate to alpha. We explore the micromechanical responses of granular heaps by DEM simulations and propose conceptual models to explain the experimental and numerical observations.