地应力条件下的凿岩爆破数值模拟

为了研究地应力对凿岩爆破的影响,采用DDA方法模拟爆炸应力波作用下考虑地应力条件时的单孔和多孔凿岩爆破破岩过程。模拟发现,随着初始地应力水平的增加,裂纹扩展半径和破岩区域面积减小,裂纹发育主方向趋于地应力的最大主应力方向,初始地应力对裂纹的抑制和引导作用明显;初始地应力水平的增加,对拉伸裂纹的抑制作用更为显著,从而降低了拉伸破坏对爆破破岩的贡献。模拟也表明,在初始地应力存在的条件下,通过对爆破载荷和炮孔布置进行针对性的优化,可以克服地应力带来的影响,并取得预期的爆破效果。本研究对地应力条件下的凿岩爆破工程具有理论和参考意义。

Numerical simulation of drilling blasting under earth stress

To investigate the influence of earth stress on drilling blasting under earth stress conditions,one-hole and multiplehole drilling blasting under the effect of explosion-induced stress waves was numerically modeled by the Discontinuous Deformation Analysis(DDA)method.The maximum cracking radius and the rock breakage area decreased with the increase of the initial earth stress level.The major direction of crack propagations coincided with the maximum principal direction of the earth stress.The capability restraining and direction guiding effects of the initial earth stresses on blasting-induced rock failures were evident.Moreover,the increasing of the initial earth stress level had a more significant restraining effect on tensile cracks,which reduced the contribution of tensile cracks on rock breakage in blasting.The influence of earth stress on drilling blasting could be conquered through specific optimization of the blasting loads and the distribution of boreholes,thus prospective rock breakage results could still be derived.It had some theoretical and instructive meanings for rock blasting engineering under earth stress conditions.