| 考虑发射电流波形的地–空瞬变电磁三分量响应研究 |
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| 引用本文： | 侯彦威,郭建磊,司银女,姜涛宁辉.考虑发射电流波形的地–空瞬变电磁三分量响应研究[J].煤田地质与勘探,2021,49(5):238. |
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| 作者姓名： | 侯彦威 郭建磊 司银女 姜涛宁辉 |
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| 基金项目： | 陕西省自然科学基础研究计划项目青年基金项目2020JQ-994中煤科工集团西安研究院有限公司科技创新基金项目2019XAYMS30 |
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| 摘 要： | 地–空瞬变电磁法在煤炭采空区勘探等领域受到了越来越多的关注, 有必要研究发射电流波形参数对地–空瞬变电磁三分量响应特征影响, 为地–空瞬变电磁数据处理与解释提供理论依据。以梯形波为例, 首先, 研究不同发射电流波形的频谱分布情况; 然后, 基于三维时域有限差分正演研究发射波形的上升沿时间、脉宽和关断时间对地–空瞬变电磁三分量磁场响应的影响。结果表明:上升沿时间对三分量二次场响应基本不产生影响; 关断时间对三分量二次场响应的影响主要集中在0.2 ms之前, 且关断时间越长对纯异常响应影响越大; 脉宽对三分量二次场响应的影响主要集中在0.1 ms之后, 且脉宽越短对纯异常响应影响越大。三维采空区模型结果表明:关断时间、脉宽对三分量异常场和背景场响应的影响特征基本一致; 通过三分量纯异常场响应多测道图和时间道图可以判断异常体的分布范围和深度。研究成果可为地–空瞬变电磁激励源波形的参数选取提供有价值的理论借鉴。
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| 关 键 词： | 地–空瞬变电磁 发射电流波形 三维时域有限差分 三分量 |
| 收稿时间： | 2021-01-06 |
Research on three-component response of ground-airborne TEM considering emission current waveform |
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| Abstract: | The ground-airborne TEM has received more and more attention in coal goaf exploration and other fields. In order to provide a theoretical basis for the processing and interpretation of ground-airborne transient electromagnetic data, it is necessary to study the influence of the transmitted current waveform parameter on the three-component response characteristics of ground-airborne TEM. Taking trapezoidal waves as an example, this article firstly studies the frequency distribution of different emission current waveform, and then investigates the effects of the rising edge time, pulse width and turn-off time of the transmitted waveform on the three-component magnetic field response of ground-air transient electromagnetic based on the three-dimensional finite difference time domain method(3D-FDTD). The results show that the rising edge time basically has no effect on the three-component secondary field response; the turn off time effect on the three-component secondary field response is mainly concentrated before 0.2 ms, and the longer the turn off time, the greater the impact on the pure abnormal response; the pulse width has the main effect on the three-component secondary field response after 0.1 ms, and the shorter the pulse width, the greater the impact on the pure abnormal response. The results of the three-dimensional goaf model show that the characteristics of the off-time and pulse width on the response of the three-component abnormal field and background field are basically the same; the distribution range and depth of anomalous objects can be judged by the three-component pure anomaly field response multi-track map and time track map. The research results will provide some valuable theoretical references for the selection of the parameters of the ground-airborne TEM excitation source waveform. |
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