As one of the factors of frequent troubles that occur in the transition period from all-coke operation to PC injection operation in blast furnace as well as increased troubles in recent years, increased size of the blast furnace and high-productivity operation are pointed out. Consequently, great importance is attached to burden distribution control and burden descent condition, or control of melting zone, deadman shape, solid flow at the lower part of furnace and others. In the present study, the reduced stockline surface profile was measured by the reflection intensity of microwave struck from the furnace top after blow-off with stockline reduced, and investigation was made on the countermeasures for changes in the raceway depth and furnace body profile during operation. As a result, it has been clarified that flow-down of coke into the lower part of blast furnace and inflow into the raceway are greatly subject to the existence of deadman which is the packed structure of the lower part of furnace, and further, they are closely related to dynamic behavior of the raceway and affect changes of the furnace body profile.
