定向爆破拆除烟囱参数的研究

Research for Directional Blasting Parameters of Removing Chimney

总结爆破拆除27个烟囱、水塔的原理、缺口和爆破参数、倾倒方向的确定等经验和研究成果。

During removing chimney by directional blasting,work made by energy from expanding air and shock wave caused by explosive blasting is utilized. Mechanical energy converted from explosive energy destroyed support structure of bottom part of chimney and created an opening, a free face. damaged chimney loses its completeness and balance. Under the action of dead weight of chimney, centre of gravity shifts, the opening is too weak to support dead weight of chimney, chimney inclines to direction of the opening, falls and leaves its base. Well done in removing chimney. Area of the opening must be larger than 2/1 area of chimney cross section; height of the opening is larger than 4/1-2/1 of chimney bottom diameter; length of the opening is 3/2 of perimeter. Depth of blast hole is equql to 0.7 thickness of chimney wall; distance between hole and hole, or hole line and hole line is 0.4—0.5 m.Industrial explosive and 1—3 stage delay detonators and millisecond detonators are used. To avoid flying debris, vibration and shock wave causing damage, chimney was covered with 2—3 ply grass bags and bamboo fence.It is necessary to control accurately inclined direction. Draw out axes of inclination direction and the opening. Blast holes are arranged at two sides along the axes. distances between hole and hole, numbers of the blast holes, charge of each hole and ignition order at the two sides are equal to each other. The author has removed 27 chimneys and water towers successfully for more than ten years.