Abstract
On the basis of the theoretical consideration of the principle of similarity in the mechanics of granular materials, a series of tests has been carried out by using a small and medium scale model of a silo. The pressure and frictional stress distributions on the wall were measured with the biaxial wall stress cells especially developed for this experiment when the granular materials were put in and drawn out of them. Silica sand and wheat were used. The following have been confirmed:
(1) The static wall stresses show values slightly greater than those calculated from Janssen's formula.
(2) In the drawing-out time, the pressure showed values 1.1 to 1.95 times larger than the static ones for silica sand, and 1.0 to 4.03 times larger than those for wheat, while the frictional stress showed values 1.08 to 8.09 times larger than the static ones for silica sand, and 1.0 to 10.35 times larger than those for wheat.
(3) The stress is proportional to the height of the silo, and the volumetric flow-out rate is proportional to the 2.5 to 3 rd power of the gate diameter of the hopper.
