NUMERLCAL SIMULATION OF INFLUENCE OF SUBDRILLING ON DEEP HOLE BENCH BLASTING

In this paper a three dimensional deep hole bench blasting model is established by 3D finite element method,and the distribution of stress field at the bottom of the bench is studied.The result shows that the shape of the effective stress field of deep hole bench blasting is quasi ellipsoid and the tip effect appears at both ends.With the increase of subdrilling,the effective stress field at the bottom is enhanced.A critical value of subdrilling exists.When subdrilling of deep hole bench blasting is greater than the critical value (Δ_h0),the effective stress at the bottom is almost the same.In this paper the critical value of subdrilling is 30 percent of burden.