Experimental investigation of ground reflected overpressure of shock wave in air blast

In order to investigate the parameters of shock wave in air blast, the ground reflected overpressures of TNT, HL0(RDX 95%+Wax 5%)and HL15(RDX 80%+Wax 5%+Al 15%) at different locations were tested. Test resultes show that the peak overpressures of HL15 are maximal at 3 m, 4 m and 5 m from the center of explosion compared with TNT and HL0. The peak overpressures of three explosives get closer to each other at 7 m, 9 m and 12 m from the center of explosion with the increase in distance. Power exponential formulas are used to fit the relationship between peak overpressure and scaled distance. The fitting results show that the magnitude order of peak overpressures is HL0≥HL15>TNT for R≤2.6 m; the magnitude order of peak overpressures is HL15>HL0>TNT for 2.6 m<R≤17.7 m. The pre-exponential factor k of HL0 is larger than those of HL15 and TNT, and the attenuation coefficient α of HL0 is larger than those of TNT and HL15. As shown above, k and α codetermine the magnitude of the reflected overpressures. In the power exponential fitting formulas, the power exponential relation of parameters gets linear after taking logarithm, and the extrapolated data obtained by formula is more close to the experimental value. The power exponential formulas could be used as empirical formulas for studying the ground reflected overpressure in air blast.