论文部分内容阅读
为观测采空区顶板诱导崩落的实施效果,研究采动影响与人工爆破强制诱导耦合作用下顶板岩体内节理、裂隙等不连续结构面的发育与矿岩破裂失稳崩落的关系,采用数字式全景钻孔摄像系统对顶板诱导崩落预裂钻孔进行了探测。探测结果表明,在实施预裂爆破钻孔内预裂缝从爆破点直至孔底,宽度达到20～40 mm,炮孔处理后至今顶板平均跨落厚度为30～40 m,诱导效果显著。岩体内以高陡倾角、窄隙宽和短隙长的次生裂隙群发育为主,微裂隙群的扩展、贯通最终导致岩体由顶板底部向上逐步剥离冒落。耦合扰动与单一采动扰动岩体内裂隙的发育情况差异明显。采用分形理论对不同钻孔同一深度的裂隙发育特征进行描述,得出不同诱导作用下岩体内裂隙数分维值及关系曲线。分析表明,诱导作用下岩体内的裂隙产生及其演化具有自相似性,其分维值随着诱导步距的推进不断增大。
In order to observe the implementation effect of caving induced roof collapse in goaf, the relationship between the development of discontinuities such as joints and fissures in roof rock mass and the failure of ore rock rupture is studied under coupling effect of mining influence and forced induction of artificial blasting. Panoramic borehole camera system to detect the roof induced caving pre-split borehole. The results show that the width of the prefracture in the blasting borehole reaches 20 ~ 40 mm from the blasting point to the bottom of the hole, and the average roof strata thickness is 30 ~ 40 m after the blast hole treatment, and the induction effect is remarkable. In the rock mass, secondary fissures with high steep dip angle, narrow gap width and short gap grow mainly. The expansion of micro-fissure group leads to the gradual detachment of rock mass from the bottom of the roof. There is obvious difference between the coupled disturbance and the single mining disturbed rock. Fractal theory is used to describe the fracture development characteristics at different depths of different boreholes, and the fractal dimension values and the relation curves of fractures within different rock mass contents are obtained. The analysis shows that the generation of fractures and their evolution in rock mass under self-similarity are self-similar, and their fractal dimension increases with the induction step.