Influence of the shapes of particle on the angle and the packing properties of granular materials was studied experimentally by measurement of the reposed angle φr, the angle of internal friction φi and porosity ε, using wood particles of various shapes as non-cohesive materials.
It is assumed in the present paper that tan φr and tan φi are apparent friction factors on the plane AB of reposed pile and the plane HH of shearing tests, respectively, as shown in Fig. 1, and the spherical unevenness as shown in Fig. 2, characterizing those planes. The shape factor ψ is defined by the ratio of the diameter of inscribed sphere to the diameter of circumscribed sphere of a particle for simplicity.
Under the above assumptions, it is supposed that the experimental curves of φr and φi vs. ψ have maximum values as shown in Fig. 5.
These results are not necessarily identical to that shown by Crosby2)and Otsubo4). The experimental curve of ε vs. ψ in Fig. 4 shows the minimum value. Nor is this result identical to the tendency of the data shown by Shirai3) and Crosby2).
From the above results and authors' considerations, it is suggested that particles differ from the symmetric to the un-symmetric in the angle and in the packing properties.