Key Technology Research Of Tunnel Receiver Combined With Magnetic Resonance Sounding And Time Domain Electromagnetic Method

The tunnel inside space is small, and even many of the height and width of the tunnel areless than2m, at present, inside of the tunnel is mainly used to detect the shape of overlappingby multi-turn means, the area is not fixed, can not guarantee the correctness of the receivedsignal, the paper developed suitable for the detection of tunnel air core coil inductive sensorsreplace multiple turns for overlapping loop devices. In our country and abroad the developinginductive sensors have several departments, including Germany, Canada, the United States, inour country has several departments o develop inductive sensors, including Jilin University,Institute of Geology and Geophysics and The Central South University, China Coal Scienceand Industry Group and other units. Existing sensors can meet the requirements of theeffective area of the tunnel, but the bandwidth is too narrow, while in the tunnel detection,blind spot too long, limits the tunnel detection range. Canadian Phoenix’s MTEM-AL sensor,the effective area is100m2, bandwidth is50kHz, the effective area and bandwidthparameters can meet the requirements of the tunnel probe, but the coil diameter is1.1m, inthe limited space in the tunnel, with central loop mode runs the coil, transmitting coil andreceiving coil due to mutual inductance generated is great, it will seriously affect the results ofthe detection, leading to inaccurate detection result; and when using dipole detectionapparatus, since the size of the transmit coil is too large, detection method is not convenient.Imported equipment costs are more expensive. Domestic commercial air-core coil sensorbasically is blank, and the majority in the development and test phase. China Coal ResearchInstitute, Xi’an Institute of Canada through the use of multifunctional Phoenix V8receiverand three air-core coil sensors make data acquisition within the tunnel; China University ofPetroleum, the Canadian company’s PRO-TEM47Geonics connection with air-core coilsensor using dipole device detection method of detecting moisture roof strata. Therefore, thedevelopment of suitable internal tunnel detection inductive sensor has important applicationvalue.Designed inductive sensors as the applications are used in the tunnel through internallaboratory experiments, shielded laboratory experiments and field experiments. In the fieldtest, carried out under the same measurement environment results made inductive coil sensor and Canadian Geonics’s3D-1HF coil, measured decay curves are basically the same,advanced noise is below3D-1HF sensor. Based on this comparison results in ShanxiShuozhou conducted field exploration test, measurement results coincide with the localgeological data.