切槽定向断裂控制爆破的数值模拟研究

Numerical Simulation on Pre-notched Directional Fracture Blast

针对切槽定向断裂控制爆破进行了ABAQUS数值模拟研究,采用内聚力模型(CZM)成功模拟了爆生主裂纹的起裂和扩展过程。数值模拟结果表明,炸药起爆后,切槽炮孔在20μs时首先在切槽尖端产生损伤,在25μs时产生爆生裂纹,并在130μs时扩展至模型边界;炮孔切槽周围形成了较强的拉伸应力区,拉应力使爆生裂纹沿切槽方向优先起裂扩展,切槽方向的最大主拉应力峰值随时间呈先增大后减小的趋势;而在非切槽方向形成了压应力区,压应力的存在限制了非切槽方向裂纹的张开;切槽方向拉应力区形成的裂纹生长区和非切槽方向压应力区形成的裂纹抑制区的共同作用,使爆生裂纹沿切槽方向起裂、扩展,并最终形成断裂面。

Using ABAQUS simulation software,the prenotched directional fracture blast was studied,as well the initiation and propagation of main blast induced-crack were modeled by Cohesive Zone Model（CZM）.The results showed that,the borehole began to induce damage in prenotched at 20 us,then crack initiated at 25 us,and eventually the cracks propagated to the boundary of model at 130us;a strong tensile stress area formed around the notch of borehole,which made the blast induced-crack initiation and expansion along the direction of pre-notch;and the maximum main tensile stress firstly increased then decreased.While,a compression stress area formed around non-notching direction,which confined the opening displacement of cracks;the common effect of a strong tensile stress area formed around the notch of borehole and a compression stress area formed around non-notching direction made cracks initiating and propagating,and eventually became surface fracture.