STUDY ON PERFORMANCE OF EXPLOSIVE CONFINEMENT STRUCTURES AGAINST INTERNAL BLAST WAVE AT SHORT RANGES

摘要

Internal explosive blast environments at short ranges and the effects of deformation and failure by them on confinement structures were rarely studied. Systematically performed theoretical and experiment research work here presents the confinement structures' anti-explosion performance under near internal explosive blast for designing relevant projects scientifically, rationally, economically and efficiently. A new approach on approximate analytical calculation of internal explosive blast has been put forward based upon theory of explosion in real air at short ranges. The flow field status and on-wall blast loads when explosive detonated in vessels were successfully simulated with the LS-DYNA code. Explosion experiment results indicate that the major response is circular stretch when reinforced concrete cylinder subjected to internal explosive blast, and explosive fractures on container are of fractal feature relative to the container's failure degree. Equivalent static loads applied on explosive confinement steel vessels are dependent not only upon the natural frequency of the vessel and the blast peak pressure, but also upon the ratio of quasi static gas pressure to the blast peak pressure. When adopting long cylindrical shell with low quasi static gas pressure and considering the favorable ductility, an explosive confinement steel vessel can be sharply lightened. The Holmquist-Johnson-Concrete model seems best fit for the concrete in layered confinement structure made up of"steel + concrete + soil (rock)". For large explosion, a compound structure of "long and thin steel sealing internal cylinder + reinforcing steel cylinders + concrete +infinite surrounding granite" appears safe, rational and feasible.