基于LS-DYNA非线性有限元程序,采用JHC混凝土损伤演化模型,研究了不同装药结构及不同空气比情况下炮孔近区混凝土损伤的破坏机理。3种装药结构计算结果表明:随着空气比的增加,破坏方式由压剪破坏转变为拉伸破坏,不同的空气比可应用于不同的爆破目的;对于梯段爆破,空气层位于上部的装药结构爆炸能量利用率最好,当空气比为40%时,炮孔中部混凝土单元破坏方式由压剪转为拉伸破坏,表明存在一个合理的空气比,可以提高爆炸能量利用率;对于预裂、光面爆破,空气层位于中部的装药结构爆破效果最优;起爆方式对梯段爆破效果的影响要比预裂和光面爆破效果明显。
Based on the non-linear finite-element procedure of LS-DYNA, the Johnson-Holmquist- Cook (JHC) model was adopted to investigate the damage evolution of the concrete near the blast hole in the cases of different charging structures and different air-decked ratios. The calculation results for three charging structures show that there is a gradual change from compression-shear failure to tensile failure with the increase of air-decked ratio and that different air-decked charging structures can be applied to different blasting purposes. For bench blasting, the highest utilization ratio of explosion energy belongs to the top air-decked charging structure. When the air-decked ratio reaches 40%, the failure mode of the concrete element changes from compression-shear failure to tensile failure in the middle of the blast hole. It is indicated that a certain reasonable air-decked ratio exists and it can be used to improve the utilization ratio of blasting energy. For presplitting blasting and smooth blasting, the best blasting effect belongs to the middle air-decked charging structure. Detonating manners can affect bench blasting more strongly than presplitting blasting and smooth blasting.