Research on evolution of shock wave of ground explosion in pit type explosion containment vessel

In order to explore the evolution of shock wave in a confined space, a pit type explosion containment vessel is designed in this paper, in which the ground explosion experiments are carried out. Four gauge points are set on the container cover to collect shock wave signals. By observing the pressure history, it was found that the shock wave experiences multiple reflections in the vessel and then tends to be stable gradually. As well as each pressure crest increases abruptly and then decays rapidly. Meanwhile, the finite element analysis program ANSYS/ AUTODYN is adopted to simulate the charge is detonated in the explosion containment vessel by the 2D axisymmetric algorithm. Observing the variation of the pressure field inside the container, it is found that the propagation velocity of shock wave in sand is obviously lower than that in air. And the intensity of the shock wave is obviously increased after reflection and interaction. As the shock wave propagates upward along the side wall of the vessel, the incidence angle of the shock wave also increases gradually. When the incidence angel reaches 47.73 degrees, Mach reflection occurs. Through analyzing the distribution of pressure field near the cover, it is found that the center and the edge of the cover suffer the impact strength and bear the serious damage risk.