2003 年 43 巻 9 号 p. 1376-1383
As the first trial in the world, the stress field in Kokura No. 2 Blast Furnace during filling and after blow-in was measured. The characteristics of transitional behavior of the measured stress field is as follows: 1) In filling process, the vertical stress at the tuyere level increased with amount of charged burden, but the rate of increase gradually dulls. 2) The high stress was observed at the central part of the furnace in comparison to the intermediate. 3) After descent occurred by the blast start, the vertical stress remarkably increased at the furnace center. 4) The origin of the change of stress field appears to be located at tuyere region as a sink of burden and the change propagates toward the furnace center.
The simulation based on elasto-plastic theory reproduces the measured value well, and the validity of the simulation method was confirmed. By use of the simulation method, the mechanism of the transitional change in stress field after blow-in is also discussed. Before blow-in, the region in passive state is not found in the furnace, and the yield region appears a little at peripheral part of the upper shaft and belly. As the descent occurs, the arched field of stress is formed above tuyere, and one end of the arch is located at the bosh wall, and the other end heads for the furnace center, i.e. deadman. The remarkable increase of the vertical stress at the furnace center after blow-in is supposed to be induced by the growth of the arch.
