应用地质雷达和钻孔窥视研究顶板裂隙分布规律

为了测定顶板岩体的结构及破坏情况,给巷道顶板支护设计提供可靠的理论依据。结合现场的实际情况,采用pulseEKKO PRO型地质雷达和钻孔窥视联合测定顶板裂隙分布规律,充分发挥地质雷达探测与钻孔窥视的优势互补作用。钻孔窥视可直观反映顶板岩体的不连续面(如层理、节理、裂隙),受现场条件影响最大钻孔深度仅4m;地质雷达精确探测距离为0~10m,可延伸至钻孔窥视盲区,对围岩裂隙不能精确描述。监测结果表明:通过分析地质雷达波形图可知结构异常区域分布在3.5m和6.3m范围内,分析钻孔窥视输出图像得到孔壁3.5m附近岩体破碎、破坏较严重,对比分析可以确定此处有顶板离层现象。由此可见,用地质雷达探测顶板岩体的结构及破坏是可行的,二者的结合既可宏观判断围岩裂隙范围,也可细观观察围岩破碎情况及裂隙方向。

Study on the distribution law of roof cracks by using geological radar and borehole peep

In order to determine the structure and damage of the roof rock mass,we combine the pulse EKKO PRO geological radar and the borehole peep to determine the distribution law of the roof cracks,which make full use of complementary advantages of geological radar and the borehole peep, which provides a reliable theoretical basis for the design of roadway roof support.Borehole peep can visually reflect the discontinuity surface of the roof rock mass (such as bedding, joints, cracks), but the maximum drilling depth is only 4m because of site condition.The accurate detection range of geological radar is 0-10m,so it can be extended to the place where the borehole peep cannot reach, but it cannot accurately describe the fracture of surrounding rock. The results show: we can see that the structural abnormalities area is distributed in the range of 3.5m and 6.3m from the geological radar waveform. We know that the rock near the wall hole of 3.5m is serious damaged from the borehole peep image. So we can determine there is roof separation. Thus, it is feasible to detect the structure and failure of the roof rock mass by using the geological radar . The combination of the two methods can not only judge the scope of surrounding rock fracture in macroscopic, but also observe the breaking situation of the surrounding rock and the direction of fracture form the micro level.