基于连续采矿的顶板诱导崩落技术,采用预裂爆破控制裂隙发展区间,强制崩顶爆破诱导顶板围岩裂隙发育、扩展,从而诱导顶板致裂失稳的可控崩落。然而在地下采空区顶板诱导致裂失稳崩落处理采空区过程中,预裂与崩顶爆破效果具有极大的隐蔽性,难以进行直观可视的评价。采用钻孔摄像系统,利用前视与全景可视技术,对顶板诱导爆破前钻孔形态和爆破的效果进行了探测,特别在爆破后的全景钻孔摄像,数字化描述了钻孔的裂隙特征,并通过钻孔摄像的图片分析评价了顶板诱导崩落爆破效果。全景探测的结果表明:(1)预裂爆破在顶板岩体中形成了清晰可见宽为20~40 mm的预裂缝,炮孔底部存在半个孔壁的预裂特征。(2)顶板围岩中产生了大量的次生诱导微裂隙带,裂隙交错呈"X"型,并且原生裂隙得到了扩展。(3)顶板诱导爆破实施后爆堆形状良好,大量裂隙发育以及碎裂岩体结构的形成有利于顶板的诱导可控崩落。
Technology of blast-induced caving roof based on the successive mining,it is said that the caving zone of fracturing are controlled through the pre-splitting blasting and inducing fracture are developed by the forced blasting.With the development and expanding of the cracks,the rock mass would have been instability and caving in the roof.But,to the process of the induction caving roof by blasting in the underground mine,the effects were invisible to the pre-splitting blasting and the forced blasting.It is difficult to quantitatively evaluate the effect of blasting.Using the borehole camera system,the technique of front view and digital panorama were used to inspect the effect of blasting.The shape of the hole-wall was detected before blasting,and the effect of the inducing fracture was inspected after blasting in the hole-wall.Especially,the cracks character was described by the digital panoramic borehole camera.The photographs were analyzed by the view and digital method.The results of the digital panoramic borehole camera show:(1) The pre-splitting cracks had been formed after pre-splitting blasting.Its width is up to 20-40 mm;and the half wall of hole could be seen in the bottom.(2) Large of secondary cracks were formed in the rock mass of roof,the crack form is "X".And the original cracks were expanded.(3) The mass shapes of blasting was right,the rock stacked by the natural angle of slope.It is advantage to induction caving roof to the large cracks and ruptured structural rock mass.