Exploration method of underground geological anomaly and its application based on directional drilling

The geological anomaly is the main hidden cause of mine disasters, and underground drilling engineering is an important technical means for exploration, verification and control of geological anomaly. In view of the shortcomings such as short distance, low accuracy and blind area of conventional drilling exploration, the exploration scheme of geological anomaly by underground directional drilling was introduced, and the identification characteristics such as spatial form, lithology and drilling were summarized. The trajectory layout principle of directional borehole was given, and the spatial calculation and positioning method of geological anomaly based on directional borehole was obtained. In addition, the influencing factors and solutions for the exploration precision of directional borehole were analyzed from four aspects: borehole layout spacing, borehole trajectory measurement and control accuracy, stratum and geological anomaly recognition accuracy, and geological anomaly development scale. The tests were carried out in Zhaogu No.2 Coal Mine and Meihuajing Coal Mine, coal seam stability of roadway strip is explored by main hole and branch hole with the exploration distance over 621 m. Water filling source in working face is explored by directional drilling group, with maximum water yield of single hole of 10.2 m3/h, then the water is discharged. The tests results show that the underground directional drilling has realized the accurate positioning of geological anomaly with the advantages of high exploration accuracy, long distance and short cycle, which provides technical support for disaster and accident prevention. © 2021 Science Press. All Rights Reserved.