露天矿临近边帮控制爆破岩石成缝机理的讨论

On Mechanism of Rock Cracking in Near Final Slope of Strip Mine in Controlled Blasting

通过预裂爆破模拟试验 ,对应力波叠加理论、爆炸气体的“气楔作用”等分别进行了验证 ,同时以爆破测震为佐证 ,从理论上否定了预裂爆破 ,并以充分的证据证明 :预裂爆破实施后 ,根本没有产生预裂缝 ,留下的半壁孔是实施主爆破时缓冲孔蓄能作用的结果 ,在此研究成果的基础上 ,提出了岩石成缝机理的回弹假说 ,并据此假说提出了一种新的临近边帮控制爆破方法—蓄能爆破。回弹假说认为爆破的真正动力源是缓冲孔 ,缓冲孔爆炸后 ,邻近边帮的岩石受到压缩产生弹性变形 ,储存了弹性变形能 ,当有了足够的补偿空间后 ,岩石在惯性作用下恢复原状 ,变形能释放产生垂直于炮孔连心线上的拉伸力 ,当拉伸力大于岩石的结构力时 ,岩石产生裂缝。

By means of the splitting blasting simulation experiment,the authors checked the theories of the stress wave superposition and the gas wedge action of the explosive gas,and on the evidence of the blasting shake measure,negated the splitting blasting in theory.It was fully proved that there was no crack left at all after the splitting blasting and the half holes left on the pit wall was the result of the elastic action which come from the buffer holes as the main blastholes was detonated.On the basis of this investigation,the authors originated the rebound gypothesis of the rock cracking mechanism and advanced a new method of controlled blasting in near final slope of open pit mine,the elastic blasting.According as the rebound hypothesis,the real power to bring the crack into being was from the buffer holes.After the buffer holes were detonated,the rock close to the pit wall was compressed,producing elastic strain and storing elastic distortion energy.As soon as there was enough compensation space,the ore was recovered to its original state by the action of the inertia,releasing the stored distortion energy producing tensile strength which was vertical to the plane in the middle of the two holes,and whenever the tensile strength was larger than the configuration strength of the rock,engendering the crack.