Yi Xiaofeng, Zhang Jian, Fan Tiehu, Tian Baofeng, Jiang Chuandong
Key Laboratory of Geophysical Exploration Equipment, Ministry of Education, Jilin University, Changchun 130061, China.
College of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, China.
Sensors (Basel). 2018 Mar 13;18(3):848. doi: 10.3390/s18030848.
Magnetic resonance sounding (MRS) is a novel geophysical method to detect groundwater directly. By applying this method to underground projects in mines and tunnels, warning information can be provided on water bodies that are hidden in front prior to excavation and thus reduce the risk of casualties and accidents. However, unlike its application to ground surfaces, the application of MRS to underground environments is constrained by the narrow space, quite weak MRS signal, and complex electromagnetic interferences with high intensities in mines. Focusing on the special requirements of underground MRS (UMRS) detection, this study proposes the use of an antenna with different turn numbers, which employs a separated transmitter and receiver. We designed a stationary coil with stable performance parameters and with a side length of 2 m, a matching circuit based on a Q-switch and a multi-stage broad/narrowband mixed filter that can cancel out most electromagnetic noise. In addition, noises in the pass-band are further eliminated by adopting statistical criteria and harmonic modeling and stacking, all of which together allow weak UMRS signals to be reliably detected. Finally, we conducted a field case study of the UMRS measurement in the Wujiagou Mine in Shanxi Province, China, with known water bodies. Our results show that the method proposed in this study can be used to obtain UMRS signals in narrow mine environments, and the inverted hydrological information generally agrees with the actual situation. Thus, we conclude that the UMRS method proposed in this study can be used for predicting hazardous water bodies at a distance of 7-9 m in front of the wall for underground mining projects.
磁共振测深（MRS）是一种直接探测地下水的新型地球物理方法。通过将该方法应用于矿山和隧道的地下工程，可以在开挖前提供前方隐藏水体的预警信息，从而降低人员伤亡和事故风险。然而，与在地面应用不同，MRS在地下环境中的应用受到狭窄空间、相当微弱的MRS信号以及矿山中高强度复杂电磁干扰的限制。针对地下MRS（UMRS）探测的特殊要求，本研究提出使用具有不同匝数的天线，该天线采用分离的发射机和接收机。我们设计了一个性能参数稳定、边长为2米的固定线圈，一个基于Q开关的匹配电路和一个能消除大部分电磁噪声的多级宽/窄带混合滤波器。此外，通过采用统计准则以及谐波建模和叠加进一步消除通带中的噪声，所有这些共同作用使得能够可靠地检测到微弱的UMRS信号。最后，我们在中国山西省吴家沟矿对已知水体进行了UMRS测量的现场案例研究。我们的结果表明，本研究提出的方法可用于在狭窄的矿山环境中获取UMRS信号，反演得到的水文信息总体上与实际情况相符。因此，我们得出结论，本研究提出的UMRS方法可用于预测地下采矿工程掌子面前方7 - 9米处的危险水体。
