COMPARISON OF THE EFFECTS OF EXPLOSIONS INITIATED AT DIFFERENT LOCATIONS IN MULTIPHASE MEDIA: AIR AND STRUCTURE

In connection with the assessment of underground structures, the question arises of the mechanical behavior of the different types of materials of the load-bearing structure exposed to the explosion and the location of its source. This means that the stresses induced by shock waves due to the explosion are in direct relation with the properties of the lining material and the location of the charge. There are a number of numerical methods that deal not only with the issue of shock waves propagation in a closed or semi-closed environment, but also nonlinear properties of the material can be described. In order to feed the numerical procedures with the relevant data, it is essential to carry out practical tests that are best in scale models, saving time and money. Recall that there are means to evaluate the actual behavior of air, structure and surrounding rocks from observation in scale models. This paper focuses on the description of concrete circular tubes simulating the tunnel in the scale of 1/20. The three-phase flow is reduced to two phases (air, structure), for simplicity. The charge is placed on the longitudinal axis and also eccentrically, for comparison. The numerical method is suggested for the completeness of the flow behavior in the multiphase medium. The overpressure exerted on the lining is monitored by sensors that are located directly above the source of the explosion, further on the distal parts of the structure and ultimately overpressure at the mouth of the tube is monitored by the so-called pencil sensor. The source of the explosion is the Semtex 1A explosive in both explosion locations.