不同耦合介质光面爆破裂纹发展数值分析

为研究不同耦合介质条件下光面爆破裂纹发展特性，基于ANSYS/LS-DYNA动力有限元程序，利用脆性材料的Von Mises破坏准则，建立了不同炮孔间距、不同抵抗线条件下的光面爆破数值模型，分别分析了空气和水作为径向耦合介质下光面爆破裂纹发展规律。研究发现：由于2种物质的性质不同，导致耦合作用机理的不同，传递给岩体的爆炸能量有所差别，进而影响炮孔间裂纹的发展，数值模拟结果证实了这一点。空气耦合下的光面爆破较易形成合格的贯通裂隙，且炮孔周边爆生裂纹相对较少，裂纹分叉现象较少；水耦合条件下贯通裂隙形成质量较低或者不形成贯通裂隙，炮孔周边裂纹较发育，裂纹分叉现象较多，不利于炮孔间径向裂纹的贯通。2种耦合介质下，炮孔连心线上的Von Mises应力衰减曲线均符合幂函数衰减，水耦合条件下，炮孔壁的Von Mises应力明显高于空气耦合，但衰减速度相比空气耦合条件下较小。随着不耦合系数的增大，传递给岩体的压力减小，岩体爆破裂纹减少，不耦合系数为2.1时爆破效果最佳。

Numerical Analysis of the Smooth Blasting Crack Development under Different Coupling Medium

In order to research the development characteristic about crack of smooth blasting under the condition of different coupling medium.The brittle material Von Mises failure criterion was applied and the model of smooth blasting with different borehole spaces and different burdens was established based on ANSYS/LS-DYNA dynamic definite programs smooth blasting crack law under the condition of coupling mediums of air and water.The results found that,as the numerical simulation confirmed,the explosive energy transmitted to rock was different and the development of crack would be influenced due to the two different medium property leading to different coupling mechanisms.The blast-induced crack surrounding the hole and crack bifurcation phenomenon was relatively small and the transfixion crack was formed easily when air as coupling medium.Under the same conditions,the quality of transfixion crack was poor or without significant crack,but the blast-induced crack surrounding the hole was development and with more crack bifurcation phenomenon which was adverse to form the radial crack between the holes.The Von Mises stress relaxation curves between the holes accords with power function relaxation under the condition of two coupling mediums,and the Von Mises hole-wall stress was obviously higher and the relaxation speed was smaller than that of air when the coupling medium was water.The simulation results also suggested that the stress transmitted to rock and blast crack would reduced with the decoupling coefficient,and the effect of smooth blasting was best when the decoupling coefficient is 2.1.