Oita Prefectural Oita Technical High School

The increase in dynamic pressure over the static one depends on the initial stress condition on the silo wall. The relationship between the increase in the dynamic pressure and the stress condition on the wall is investigated by specifying the major principal stress direction on it. The stress condition is produced on the wall by taking the low rate feeding results in a structure with unstable static doming in the shallow portion and with stable squashed doming due to its own weight in the deep portion of the silo. Under this condition, large dynamic over pressure takes place on the foot of the critical height Hc for the yield at which the lowest dome is almost squashed. The stress condition on the wall is determined by taking the high rate feeding results in the structure with the compacted stress condition, under which Mohr's circle has switched continually to new Morh's circle with a large stress radius keeping the critical condition for yield in bulk (point B in Fig. 8). Under this condition, the overpressure ratio shows a value smaller than 1.0, and dynamic wall pressure becomes smaller than that in static conditions due to decreasing stress radius. The highest possible feeding rate is recommended with the view of decreasing the dynamic over pressure