Stationary Cone Particles Heap Stress

The cause of stress dip was studied all along by physical scientist. The stress distribution in the conic piles must be understood to show the reason of stress dip. An experiment was designed to measure distributions of tangential stress on bottom of conic piles, formed by pureeing granular materials from a fixed point with a same flux, on two planes of different roughness. The results show that the stress depends on the plane roughness: The rougher one has the stronger stress. Using the general equations of force balance, Coulomb inequality and free boundary conditions for side surfaces of the piles, it could be shown that the strength of tangential stress are related with dip observed in distribution of normal stress: Namely a stronger tangential stress has a more notable dip. We proposed a function that shows the distributions of tangential stress along radius, and then figured out the stress distribution in the pile base on the function. The results are in according with the measured data. We got the outcomes below based on above: (1) The distribution of tangential stress along the radius on bottom of conic piles can been depicted by quadratic function. (2) The stress dip depends on the plane's roughness. (3) The tangential stress on bottom of conic piles influence the intensity of the tress dip. The paper hasn't presented a basic theory to explain the function it had gotten, but the result will be beneficial to founding a basic theory and the way of experiment in this paper can advance the studying on granule materials.