煤矿巷道直流三极法超前探测的可行性

The feasibility of advanced detection using DC three-electrode method in coal-mine tunnel

全空间巷道超前探测由于受到掌子面前方及上下左右岩土介质的影响异常要复杂许多,应用直流电阻率法进行超前探测也会遇到同样的问题.本文从理论计算和三维数值模拟两个方面分析了直流电阻率三极测深法超前探测的能力,结果表明:在理想情况下,当掌子面前方存在一定规模的低阻体时只能引起巷道底板上三极测深视电阻率曲线单调下降,且影响很小,仅凭几条这样的曲线还无法判断低阻体的空间位置.因此,目前在煤矿巷道广泛使用的三极超前探测方法前景令人担忧.

The anomaly of whole space advanced detection is extraordinarily complicated under the impact of geo medium in front of tunnel face and around the tunnel. This problem can also be encountered when using DC resistivity method. The ability of advanced detection using DC three-electrode method is analyzed by theoretical calculation and three dimension numerical simulation. The result indicates that： the response of DC three-electrode method under the ideal condition can reflect the low resistivity body in front of the tunnel face. It means the apparent resistivity curve decreases monotonically. However, the spatial position of the low resistivity cannot be judged only by these curves. Therefore, the three-electrode advanced detection method which is widely used in coal mine tunnel does not have a good outlook.