Abstract:In order to fast calculate the blast wave peak overpressure under complex environments, by utilizing the dimensional analysis (DA) method, a qualitative function relationship of the blast wave peak overpressure of the explosion in free air has been derived, and then, based on the Taylor expansion, a polynomial form function was obtained. By analyzing the physical meaning of the polynomial function, the concept of energy concentration factor (ECF) has been introduced, and by employing the ECF, the polynomial function of the blast wave peak overpressure of the explosion in free field was extended to complex environments in engineering applications. The physical and mathematical rationality of the widely used empirical formulas for the peak overpressure in free field explosions were verified by the polynomial function derived in this paper. Analytical calculation formulas of blast wave peak overpressure for some complex configuration cases, such as the free hemispherical rigid ground explosion, the two open-end tunnel explosion, the one closed-end tunnel explosion, the crossed tunnel explosion, the open-sided multi-storey buildings explosion and the long straight street explosion, et al, have been got by the ECF method. The comparison of the analytical calculation results in this paper with the experimental and numerical results indicates that the analytical results agree very well with the experiments and numerical simulations.