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

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.