异形孔水包爆破数值模拟及现场试验

Numerical Simulation and Field Experiment of the Blasting Technology withWater Bags in Notched Holes

为了提高隧道光面爆破效果,提出异形孔水包爆破技术。以径向不耦合装药和间隔装药的岩石损伤、径向和轴向的爆破效率、径向孔壁压力和现场周边孔炮痕率、岩石破碎情况、隧道超欠挖情况为依据,分析其爆破效果。结果表明:(1)径向不耦合系数的改变对轴、径向爆破效果有影响,间隔装药系数的改变仅对轴向和孔间爆破效果有影响;(2)当K_(d)=1.25时,岩石破坏区集中发生在炸药孔间内,岩石轴向破坏区较小,当K_(d)=1.75时,过量水包出现耗能现象,岩石破坏区较小;(3)异形孔水包爆破技术能产生光滑的隧道开挖轮廓线,渣石更破碎,K_(r)=1.5和K_(d)=1.5为其最优装药系数。

In order to improve the effect of smooth blasting in tunnelling,this paper proposes the blasting technology with water bags in notched holes.It also analyzes the blasting effect based on the rock damage induced by radial de⁃coupling charge and spaced charge,the blasting efficiency in radial and axial directions,the radial pressure on the hole wall and mark rate of perimeter holes at site,the rock fragmentation,and the overbreak and underbreak of the tunnel.The results show that:(1)The change of radial decoupling coefficient has an effect on the axial and radial blasting effects,and the change of spaced charge coefficient only has an effect on the axial and inter-hole blasting effects;(2)when K_(d)=1.25,rock damage is concentrated in zones between the explosive holes,and axial rock damage zones are relatively small;when K_(d)=1.75,excessive water bags would induce an energy dissipation,and the rock damage zones are smaller;and(3)the blasting technology with water bags in notched holes can produce smooth tunnel contour profile,with more finely broken rock mucks,and the optimal charging factors are K_(r)=1.5 and K_(d)=1.5.