钻孔瞬变电磁(BTEM)扫描探测方法可以利用巷道已有超前探查钻孔，通过旋转置于钻孔内收发线圈对孔壁外围隐蔽地质异常体进行扫描探测，因收发装置位于钻孔内,不仅避免了巷道内电气设备和金属物的电磁干扰，而且可以提高钻孔利用率，减少钻探工作量。然而，钻孔瞬变电磁法受全空间效应的影响，在扫描探测过程中，以收发线圈法线方向为探测方向接收异常体二次场信号的同时，还易受到其他方向信号的叠加干扰。若无法有效压制干扰信号，将直接影响对钻孔孔壁外围地质异常体的精确定位。利用屏蔽的方法，在接收线圈上安装屏蔽罩，尽可能保留线圈法线与屏蔽罩开口一致的探测方向的响应信号，而对其他方向的信号进行压制，从而实现钻孔孔壁径向一定范围内指向性探测。首先通过物理模拟实验探讨了不同匝数、尺寸的收发线圈对瞬变电磁场响应特征的影响，对适用于钻孔内的收发线圈参数进行组合优选。然后针对所要屏蔽的电磁波，选择不同种类的屏蔽材料，开展不同材料对不同方向电磁波的屏蔽效果实验。通过对比探测方向和其他方向的感应电动势，证实以泡沫镍制作的屏蔽罩能有效地压制非探测方向的干扰信号。通过实验分别对屏蔽罩的不同形状、磁导率等物性参数进行瞬变电磁场响应特征对比分析，并探讨屏蔽罩开口角度与定向屏蔽效果的关系，优化定向屏蔽罩参数，增强屏蔽效果。最后使用参数优化后的收发线圈和定向屏蔽装置进行钻孔瞬变电磁法径向断面扫描探测现场实验，采用基于混合分布的混沌量子粒子群和Levenberg-Marquarat及Occam组合算法的反演方法进行电阻率成像。研究表明：以泡沫镍为屏蔽材料，安装在接收线圈上的弧形屏蔽罩定向屏蔽效果较好，可以有效地压制钻孔瞬变电磁法扫描探测过程中非探测方向的信号干扰，且能较大程度的保留探测方向的异常响应信号，进而可以实现对钻孔孔壁外围隐蔽地质异常体的精确定位。

Borehole transient electromagnetic(BTEM)scanning detection method uses the advanced exploration boreholes in the roadway to scan and detect the hidden geological anomalies outside the borehole wall by rotating the transceiver coil inside the borehole. Because of the transceiver device is located in the borehole, it not only avoids the electromagnetic interference of the electrical equipment and metal in the roadway, but also improves the utilization rate of the borehole and reduces the drilling workload. However, the BTEM is affected by the whole space effect. In the scanning and detection process, the normal direction of the transceiver coil is used as the detection direction to receive the secondary field signal of the abnormal body, it is also susceptible to the superposition interference of signals in other directions. If the interference signals cannot be effectively suppressed, it will directly affect the positioning of the geological anomaly body around the borehole wall. Using the shielding method, the shielding cover is installed on the receiving coil, and the response signal in the detection direction where the coil normal line is consistent with the opening of the shielding cover is retained as much as possible, while the signals in other directions are shielded, so as to realize the directional detection of the radial direction of the borehole wall within a certain range. First of all, the influences of transceiver coils with different turns and sizes on transient electromagnetic response characteristics are discussed through physical simulation experiments, and the parameters of transceiver coils suitable for drilling are optimized. Subsequently, aiming at the electromagnetic wave to be shielded, different kinds of shielding materials are selected, and the shielding effect experiments of different materials on electromagnetic waves in different directions are carried out. By comparing the induced electromotive force of the detection direction and other directions, it is proved that the arc-shielding made of nickel foam can effectively suppress the response signal in non-detecting direction. The transient electromagnetic field response characteristics of different shapes, permeability and other physical parameters of the shield are compared and analyzed through experiments. Relationship between the opening angle size of the shield, the distance between the shield and the receiver coil and the directional shielding effect is discussed. The parameters of the directional shielding are optimized to enhance the shielding effect. Finally, the parameters optimized transceiver coil and directional shielding device are used to carry out the borehole transient electromagnetic method radial section scanning detection field experiment. The inverse method based on a mixed distribution chaotic quantum particle swarm optimization and a combined Levenberg-Marquarat and Occam algorithms is used for resistivity images. The research shows that the arc-shaped shielding cover installed on the receiving coil with foam nickel as the shielding material has a better directional shielding effect, which can effectively suppress the signal interference in the non-detection direction during the scanning detection process of BTEM and can retain the abnormal response signal in the detection direction. Therefore, the precise positioning of the hidden geological anomaly body around the borehole wall can be realized.