Experimental Research on the Influence of an Empty-Hole Defect on Crack Connections Between a Directionally Fractured Blast Hole

摘要

In this work, we examine the distribution characteristics of a dynamic stress field surrounding an empty hole, as well as the influence of an empty hole on the dynamic behavior of main crack expansion caused by an explosion between double blast holes from a blast load effect by utilizing a new digital laser dynamic caustics (DLDC) experimental system. The results show that the two face-to-face expanded main cracks are deflected toward the empty hole and connect at the empty hole as a result of the influence of the guiding role of the empty hole. The influence of increasing the size of the empty hole on the orientation of the principle stress surrounding the empty hole is found to be ambiguous. The expansion speed and stress-intensity factor of the main crack tips in each case are analyzed. Moreover, the average expansion speed of the main crack for different shapes of empty holes are compared.