Abstract
By using a simple rectangular frame in which steel balls of equal diameter were placed in one layer, bi-axial compression tests were carried out to observe the influence of grain-to-grain friction on the shear phenomena of a granular material. Since the distribution of the void ratios was considered important, photo-cells were used to measure the void ratios at many points within the steel ball layer. The average value and the variance of the void ratio distribution which changed with shear were computed and were compared among the results obtained for various densities of steel ball packing. A series of tests were conducted on steel balls with rough surface and those with smooth surface. The difference in the behaviors of these two kinds of steel balls was studied in terms of the difference in the surface roughness. The results obtained were discussed in connection with the theory proposed previously by the senior author.
