Study on the Reasonable Parameters of the Concentric Hemisphere-Style Shaped Charge for Destroying Rock

Currently, increasing the ratio of useful energy for external charge to destruct rock is a necessary research direction. Therefore, using an analytical method, this study established the dependence of the explosive force and the productivity of using energy for the concentric spherical shaped charge on the uniform-geometric characteristic parameters of this shaped charge. A computational programme was developed in the MATLAB software to calculate, investigate and analyse the abovementioned rule of dependence. The analysis and evaluation of this rule combined with the analysis of the purpose of the rock obstacle destruction allow to select reasonable uniform-geometric characteristic parameters of the concentric hemisphere shaped charge. The model is designed and created for selected concentric hemisphere shaped charge to fill 40 g of plastic explosive C4. The surface of the inner hemisphere of this shaped charge is a hemisphere lining funnel that is made of steel with a thickness of 1 mm. Tests were conducted, and the explosion efficiency of the concentric hemisphere concentrated shaped charge model was compared with that of the normal concentrated charge with the same 40-g explosive amount. The obtained results show that the productivity of concentric hemispheres shaped charge is 2.7 times higher than that of the concentrated charge. Furthermore, in the experiments for grade M300 concrete samples, the destructive zone volume of the proposed hemispherical shaped charge was approximately 2 times higher than that of the conventional concentrated charge. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.