Effect of Air Position to the Mechanism of Air-Decked Blasting

Abstract

Based on the JHC model of concrete damage evolution, the dynamic stress characteristics and failure mechanism of blast-hole near-field about different air-decked charge structures are studied by numerical simulation. Result shows that the failure mechanism of typical elements changes from compression-shear failure into shear-tensile failure gradually with the increase of their position in indirect initiation of both top-air-decked and bottom-air-decked charges, because of the affecting factors of the freedom and the loading from the hole. If middle-air-decked charges detonate from the top and bottom at the same time, loading and unloading waves in blasting hole are more influential to the damage of bottom elements than the surface freedom, because detonation waves of both top and bottom meet at the middle hole, so it is conducive to the media failure at the bottom hole, the elements of freedom surface have the same failure properties to top-air-decked charge.