煤巷多点电流源双频激电法超前扫描探测技术

Study on advanced scanning detection technology of dual-frequency induced polarization method with multi-point current sources in coal mine roadway

  • 摘要: 在掘进工作面上设计多点电流源双频激电法探测电极布置方式,根据稳定电流场性质,建立多点电流源电场线微分方程,基于变步长四阶五级Runge-Kutta-Felhberg算法,对微分方程组进行求解。定义探测电场空间立体角和电场线边界角概念,分析探测电场平均电流密度随主屏流比系数及距掘进断面距离变化规律,确定聚焦效应探测时主屏流比系的取值范围。同时改变约束屏流比系数和主屏流比系数,分析探测电场偏转角的变化规律及对其影响的主要因素,确定偏转效应探测时约束屏流比系数的取值范围。工业性试验表明:利用该方法进行超前扫描探测,根据视幅频率和视电阻率异常激电效应参量变化规律,能够有效识别工作面前方围岩地质构造特征及低阻含水异常体的方向,但含水异常体距工作面的准确距离和含水量的大小尚需进一步研究。

     

    Abstract: The detection electrode arrangements of dual-frequency induced polarization method with multi-point current sources are designed in the heading face. According to the properties of stable current field, the differential equations of electric field lines with multi-point current sources are established and solved based on the fourth fifth-order variable step Runge-Kutta-Felhberg algorithm. Through defining the concept of detection field spatial angle and electric field lines boundary angle, this paper analyzes the average current density of the detection field variation with the main shielding current ratio coefficient and the distance from heading face to determine the range of the main shielding current ratio coefficient at focusing effect detection. When the constraint shielding current ratio coefficient and the main shielding current ratio coefficient are changed simultaneously, this paper analyzes the detection field deflection angle variation and its influence factors to determine the range of the constraint shielding current ratio coefficient at deflection effect detection. The industrial tests show that according to abnormal induced polarization effect parameters variation of the apparent frequency and the apparent resistivity, using this method for advanced scanning detection can effectively identify the geological structure characteristics of the surrounding rock and the direction of the low resistivity water-bearing anomaly in front of the heading face, but the accurate distance and the water content of the water-bearing anomaly are still need to be further studied.

     

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