巷道前方含水体的瞬变电磁响应及探测技术研究

发布时间：2018-06-08 08:03

本文选题：巷道超前探水 + 瞬变电磁法　；参考：《安徽理工大学》2014年博士论文

【摘要】：近年来,随着我国煤炭资源开采向深部发展,巷道掘进呈现出多灾源地质特征,水害作为其中一个主要因素,已经严重影响到煤矿安全生产。当前,瞬变电磁技术已成为巷道掘进超前水害探查的主要手段之一,但受仪器设备、数据采集方式、数据处理与解释方法等限制,其测试效果还不能满足实际生产需求,因此积极开展巷道瞬变电磁超前探测技术研究具有重要的理论和实践意义。论文以现有研究成果为基础,对巷道掘进瞬变电磁超前探水技术进行研究,其中：(1)通过对巷道瞬变电磁探测常规理论及解释方法的总结分析,推导了多匝方形小回线源瞬变场的阶跃响应公式,误差分析结果表明了其准确性；(2)通过对Maxwell方程组的时域有限差分算法进行系统研究,特别是对其中瞬变场源的设置进行改进,基于VC++.Net编制了3D FDTD程序,并结合巷道掘进地质条件,选择巷道前方立方体、板状体及柱状体含水模型进行数值模拟,揭示了不同模型条件下瞬变场的全空间扩散规律及回线中心异常场响应特征；(3)通过对数据采集系统、数据处理与解释方法研究,改进并形成了一整套巷道瞬变电磁超前探测技术。其中通过对仪器主机功能及参数、回线装置形式及阻尼状态进行优化与匹配,提高了实测瞬变场数据的采集精度,特别是增强了早、中延时段数据采集质量的可靠性。结合巷道测试条件,对现有三断面观测方式的特点进行分析,提出四断面超前探测布置方式,增强对现场数据的观测力度。考虑仪器实际探测时存在电流关断时间,在充分分析关断时间对瞬变场源激励频谱和瞬变场的影响范围基础上,推导全空间条件下全程视电阻率计算方法,并通过对扇形观测条件下,不同角度测点在巷道前方形成的烟圈交汇特征分析,提出视电阻率扩散叠加解释方法；(4)针对掘进工作面干扰因素中锚杆干扰进行实验探讨,通过对井下两根锚杆的测试,获得了锚杆的干扰范围及不同范围的干扰程度,一定程度上为现场数据采集与校正提供依据。通过构建井下水仓模型,对巷道前方25m处100m3水仓水量及其瞬变场响应的动态观测,获得巷道前方弱含水体的瞬变场响应特点。理论数据、物理实验及现场探查应用结果表明,改进形成的瞬变电磁超前探水系统对瞬变场数据采集具有优越性,其超前探测的电性成像效果良好。通过理论与实践研究,论文取得了对巷道瞬变电磁超前探水的诸多认识,所形成的瞬变电磁测试技术系统在现场探测中实用性强。由于瞬变电磁探测系统较为复杂,受时间限制,今后还需要在探测基础理论、含水体弱信号提取、现场干扰因素校正等方面进行深入研究,为进一步提高掘进探水效果奠定坚实基础,确保巷道掘进的安全生产。
[Abstract]:In recent years, with the development of coal resources in China, the roadway excavation presents the geological characteristics of multiple disaster sources. Water hazard, as one of the main factors, has seriously affected the safety of coal mine production. At present, transient electromagnetic technology has become one of the main means to detect water hazards in advance of roadway excavation. However, due to the limitation of instruments and equipment, data acquisition methods, data processing and interpretation methods, the test results can not meet the actual production requirements. Therefore, it is of great theoretical and practical significance to actively carry out the research on the transient electromagnetic advance detection technology of roadway. Based on the existing research results, this paper studies the transient electromagnetic advance water detection technology of roadway tunneling. By summing up and analyzing the conventional theory and interpretation method of transient electromagnetic detection in roadway, the step response formula of multi-turn square small loop source transient field is derived. The error analysis results show its accuracy. (2) through the systematic research on the finite difference time-domain (FDTD) algorithm of Maxwell equations, especially the improvement of the setting of transient field source, a 3D FDTD program based on VC. Net is developed. Combined with the geological conditions of roadway excavation, the water content models of cube, plate and column in front of roadway are selected for numerical simulation. This paper reveals the whole spatial diffusion law of the transient field under different model conditions and the response characteristics of the anomalous field in the center of the loop. The data acquisition system, data processing and interpretation methods are studied. Improved and formed a set of tunnel transient electromagnetic advance detection technology. By optimizing and matching the functions and parameters of the instrument mainframe, the form of loop device and the damping state, the acquisition accuracy of the measured transient field data is improved, especially the reliability of the data acquisition quality in the early and middle delay section is enhanced. Based on the test conditions of roadway, the characteristics of the existing observation methods of three sections are analyzed, and the arrangement of advance detection of four sections is put forward to enhance the observation intensity of the field data. Considering the existence of current turn-off time in the actual detection of the instrument, on the basis of fully analyzing the influence of turn-off time on the excitation spectrum and transient field of the transient field source, a method for calculating the full-range apparent resistivity under the full space condition is derived. By analyzing the characteristics of smoke ring intersection formed in front of roadway at different angle measuring points under the condition of fan shape observation, a superposition interpretation method of apparent resistivity diffusion is put forward in this paper. Through the test of two anchors underground, the interference range of the bolt and the interference degree of different range are obtained, which provides the basis for the field data collection and correction to a certain extent. By constructing the underground water bunker model, the dynamic observation of the water quantity and its transient field response of 100m3 silo at 25m in front of the roadway is carried out, and the characteristics of the transient field response of the weakly water bearing water in front of the tunnel are obtained. The theoretical data, physical experiments and field exploration results show that the improved transient electromagnetic advanced water detection system is superior to the transient field data acquisition, and the electrical imaging effect of the advanced detection is good. In this paper, a lot of understanding of the transient electromagnetic advance water detection in roadway has been obtained, and the transient electromagnetic testing system has been formed, which is very practical in the field detection. Due to the complexity of transient electromagnetic detection system and the limitation of time, it is necessary to further study the basic theory of detection, the extraction of weak signals with water content, the correction of field interference factors, and so on. It lays a solid foundation for further improving the water exploration effect of tunneling and ensures the safe production of roadway excavation.
【学位授予单位】：安徽理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P631.325;TD745

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