Shock Wave Stress Concentration to Solve Large Drill-Jamming Problem

We put forward a new specialty blasting method to solve drill-jamming based on stress concentration and stress wave theory. Drill-jamming accident of banji was successfully solved at the early 2006 through this method first: for this drill-jamming, study drilling tools and location of drill-jamming to find the weak position (Fig. 1); produce impact loading and form stress concentration (Fig. 3) at weak position by place well-designed explosive package at special position. Through many times controllable safe explosions and repeatedly impact loading, accurate fracture, separate sinker bar and the above parts from drill bit, this part raised up successfully (Fig. 7). The rest would be taken out after second reaming.