Water-Cased Kicker Charges for Use in Explosive Demolition

Abstract

Demolition projects involving explosives often incorporate cutting charges to sever columns in conjunction with kicker charges that “move” the columns out of alignment. Traditional kicker charges use dynamite secured to the column above a linear-shaped cutting charge. This study investigates the use of water-cased kicker charges for use in explosive demolition. The goal is to reduce the fragmentation of steel members and the quantity of explosive needed due to the increased density, incompressibility, and impedance mismatch water provides. Simulations and experimental tests were utilized to determine what type of charges provide the optimal column movement and water placement. Water charges and traditional charges were placed on hanging steel columns that swung freely from a top pivot and analyzed for the fragmentation and velocity of the column. Tests were recorded with high-speed video to calculate velocity and impulse. Simulations showed the same results as experimental tests, with water-cased charges moving the column faster and with more impulse than traditional charges. Experimental testing showed that water-cased charges moved the column 53% faster than traditional in contact charges while simulations showed that water-cased charges moved the column 43% faster than traditional in contact charges. Simulations showed the water tamped behind the charge increased beam velocity 32% while water in front of the charge reduced pressure 38% through dispersion.