Damage behavior of the surrounding medium caused by different blast-induced dynamic and static loadings

•Applied three kinds of explosive to generate the different strength dynamic and static loads.•Schlieren method to study the dynamic evolution process of explosion products in air field.•Caustic method to study the damage behavior of PMMA under different explosion loads.•Explosion dynamic load play a key role in crack initiation.•Explosion quasi-static load dominates the process of crack propagate. The combination of the dynamic action of explosion stress wave and the static action of explosion gas expansion is what primarily drives rock-breaking blasting, and their different intensities lead to different blasting effects. Therefore, experiments were conducted to explore the damage behaviour of the surrounding medium caused by different blast-induced dynamic and static loadings using digital laser Schlieren and digital laser dynamic caustic systems. The results were as follows: In the air medium, when the explosives detonated, TATP (triacetone triperoxide) had the strongest quasi-static effect, and the highest velocity explosion shock wave and products compared with those of NHN (nickel hydrazine nitrate) and DDNP (diazodinitrophenol). Part of the TATP explosion product was ahead of the shock wave front, whereas for NHN and DDNP, their explosion products were behind the propagation of the shock wave front. The highest pressure peak of TATP was the result of the combined action of the shock wave and explosion product impacting the sensor. In the solid medium, NHN, the explosive with the strongest dynamic load, had the strongest stress wave and highest stress intensity factor peak of the main crack. The velocity reached the peak value at the early stage of propagation, and the dynamic action had a dominant effect on the cracking of the crack; the stronger the dynamic action, the higher the crack initiation energy. The stress intensity factor and propagation rate of the main crack of TATP with the strongest quasi-static effect decreased slower than those of the other explosives; therefore, the main crack propagation time and length were the longest. After cracking, the quasi-static effect dominated the process of crack propagation, where the stronger the quasi-static effect, the longer duration of the driving force of crack propagation. The research results provide a basis for customising explosives for different functions in practical engineering and realising the fine and efficient utilisation of explosion energy.