Theoretical calculation of wall pressure in a granular material filled in hoppers or bin-hopper systems was made under stationary and flowing conditions. In the latter case, some assumptions proposed by Gardner and Walker were adopted.
Measurement of the wall pressure was also carried out using a wire resistance strain gage. It has been concluded that when a mass flow of granular materials occurs in the vessel, the pattern of distribution of the wall pressure qualitatively agrees with the theoretical curve except for the region near the hopper outlet, where the effect of dynamic pressure of particles prevails. On the other hand, when plug flow takes place, the wall pressure does not change from the value of stationary state in the upper part of the vessel, while it increases toward the outlet in the lower part of the vessel.