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When the traditional single point power supply electrode DC advance detection technology is used to detect the long-distance anomaly, the signal gradually weakens and the accuracy greatly decreases with the increase of detection distance. In order to solve the problem of large error in long distance advance detection, we combine the existing DC method advance detection technology to change the power supply from single point source to three-point source, use COMSOL software to simulate, draw the apparent resistivity curve of the survey line, and draw the apparent resistivity profile through SURFER. The results show that the three-point source power supply can better reflect the location of the remote abnormal body, increase the effective distance of advance detection, and improve the accuracy of advance detection.

In order to study the feasibility of mine DC quadrupole device in advance detection of tunneling roadway, a 3D geoelectric model of roadway advance detection is established, and ANSYS is used to simulate quadrupole device for data acquisition; the ratio method is used to eliminate the influence of interference factors such as roadway and device, and the collected data without the influence of roadway is compared with the collected data; three full space geoelectric models are established to study the response of quadrupole device to different abnormal body positions, and the response characteristics of quadrupole device to low resistance abnormal body are obtained; the practicability of this method is illustrated by an engineering example. The research results show that the ratio method can eliminate the influence of the roadway on the abnormal body, and realize the advance detection of the roadway with the quadrupole device. It is feasible to use the quadrupole device to collect data in the advance detection of the roadway.

To prevent the occurrence of water inrush from the working face floor, explorations of water-rich floors are necessary. For a working face with a regular shape, a water-rich floor can be detected by laying electrodes and cables around the working face. However, the rectangular working face develops an irregular shape, and the exploration of water in irregular working faces is a difficulty in the study of 3D electric resistivity tomography (ERT). In this paper, an unconventional dipole–dipole array is used for data acquisition and the potential of a non-grid point electrode is replaced by the potential of the surrounding electrode, which identifies a water-rich floor using 3D ERT with arbitrary electrode positions. Taking the 8826 irregular working face of the Baizhuang coal mine as an example, the working face is explored by 3D ERT, the anomalous area is delineated, and targeted grouting is carried out in the anomalous area. After grouting, the grouting effect is detected by 3D ERT, and the safe mining of the working face is ensured. The results show that grouting effect detection within the floor of a coal seam using 3D electric resistivity tomography (ERT) with arbitrary electrode positions could be applied to solving the problem of water-rich exploration of floors in irregular working faces. [ABSTRACT FROM AUTHOR]