【摘要】 为了研究隧道瞬变电磁超前探测中不同装置型式对采集数据和成像结果的影响,通过数值试验和现场试验对比了4种掌子面收发装置布设方式:即中心回线装置和3种偶极装置(分别为固源直线接收偶极装置、固源拱形接收偶极装置、固源等距接收偶极装置)。采用时域有限差分方法对掌子面前方包含直立含水断层和倾斜充水断层进行正演计算,对模拟曲线进行了对比和分析;并利用某水电站现场的已知试验条件进行试验数据采集;数值和现场试验的数据均采用全域视电阻率计算方法进行视电阻率成像。通过数值试验和现场试验对比,发现4种装置型式均可以成像确定含水体位置,但不同装置型式的探测结果有所差异:(1)固源直线接收偶极装置对于识别含水体的位置和形态最为有效;(2)中心回线装置能够有效识别含水体的位置,但是识别含水体形态效果不好;(3)固源等距接收偶极装置对于含水体形态识别能力较好,但是识别含水体位置能力不强;(4)固源拱形接收偶极装置识别含水体的位置和形态都不理想。综上所述,固源直线接收偶极装置对于识别含水体的位置和形态在4种装置型式中最为有效,而且发射源固定于掌子面,只需移动数据接收机,易于提高工作效率。更多还原

【Abstract】 In order to study the influence of different configurations on the acquisition data and imaging quality in the tunnel transient electromagnetic(TEM) detection,four configurations,which contain central loop and three different dipole-dipole(fixed transmitting line moving receiver,fixed transmitting arch moving receiver,fixed transmitting loop and receiver distance),are researched by numerical and field experiments. In numerical test,both vertical and titled water filled fault models are studied using 3D finite difference time domain(FDTD) method,and electromagnetic response is analyzed and researched. In field test,a known experimental site in hydropower station is used to collect electromagnetic field data. Numerical and field test data utilize full-time apparent resistivity calculation method to image the apparent resistivity. The numerical and field test found that four configurations can locate the water position,but different configuration has different phenomenon. Firstly,the fixed transmitting line moving Receiver dipole configuration is most effective to identify the position and shape of water filled fault;Secondly,the central loop configuration can effectively identify the location but not good at recognizing the shape;Thirdly,the fixed transmitting loop and receiver distance dipole configuration is good at recognizing the shape but not good at finding the location;Lastly,the fixed transmitting arch moving receiver dipole configuration cannot effectively identify the location and shape. All in all,the fixed transmitting line moving receiver dipole configuration is the most effective method to identify the location and shape of water filled faults in tunnel detection of TEM,and transmitting loop is fixed on the tunnel face, we just move the receiver to improve work efficiency.更多还原