Three-dimensional transient electromagnetic detection technology of fixed point in full space

In order to accurately locate and intuitively display the water-conducting structures inside the front of the excavation roadway and in the working face in the results map, based on the original fixed-point three-dimensional transient electromagnetic advance detection technology, the three-dimensional physical simulation technology was used to simulate the water-conducting structures in different spatial locations and shapes in coal mines, and the spatial distribution characteristics of three-dimensional apparent resistivity were analyzed. The results show that the multi-turn small coil has certain directionality. When the normal line of the transceiver coil is close to the simulated body, it will produce a more obvious transient electromagnetic response signal; the water-repellent model with different position and shape, the apparent resistivity of the three-dimensional space of equipotential surface area basically coincides with its actual volumetric dimension. In the application of concealed collapse columns inside the working face 19108 of Jinggongyi Mine No. 1 in Pingshuo, the collapse columns inside the working face can be accurately displayed in the three-dimensional anomaly space, providing effective technical means for geological forecast during drivage excavation and before extraction in a working face.