Mechanism of rock directional fracture when blasting with dynamic caustics

In order to make further quantitative analysis on crack propagation under blasting load, the paper first gives a method to research blasting mechanism with dynamic caustics. An experiment was conducted in which transmitted dynamic caustics under blasting load have been traced in a transparent material model, and a series of dynamic caustics photos were obtained. This paper also discusses the general law of crack propagation in slotted cartridge blasting and analyses the stress intensity factor around the crack tip in the progress of crack directional propagation quantitatively. The influence of slot width on the control effect of directional fracture is probed.