【作者】 张晓峰；

【导师】 冯兵；

【作者基本信息】 长安大学 ， 地球探测与信息技术， 2007， 硕士

【摘要】 在煤矿生产过程中,随着煤层的被开采挖掘,地下会形成越来越多的采空区。采空区的垮塌会造成地面下沉、裂缝,毁坏耕地、建筑物等设施,破环生态环境。故有效而经济地利用物探方法对采空区域进行勘探和评价,并提出适宜的防治措施有着良好的经济效益和社会效益。近年来众多物探工作者对其进行了研究,取得了很多实用性的成果。但总体来讲,采空区的勘探研究还处于发展阶段,勘探手段和理论均不完善。国内外在此方而的成功经验和资料积累大体包括:收集资料和调查访问、钻探、室内试验、数值模拟等。首先,本文简要介绍了瞬变电磁法的发展概况及主要工作装置,总结了该方法技术的主要优点,较详细地分析了均匀半空间,电磁场的特征,推导了早期、晚期及全期道视电阻率ρ_τ公式以及高阻围岩中局部导电体的瞬变电磁响应和相应的ρ_τ公式。探讨了TEM附加效应的产生原因及识别方法、消除或削弱途径;总结了同点装置物理模拟异常剖面曲线特征。从影响瞬变电磁法几种主要因素入手,探讨了压制地质噪声的途径,明确了回线边长与探测深度、供电电流与信噪比的关系。其次,讨论了不同方式采煤所形成的不同类型地下采空区及地电特性的关系,认为煤矿机械化程度高或规范开采所形成的采空区,对上覆岩层的破坏程度大,产生的裂缝数量多且塌陷面积广,其电性特征是视电阻率值低且分布范围大,规律性明显,易分辨。而煤矿机械化程度低或不规范开采所形成的采空区,对上覆岩层的破坏程度较小,也可形成规模不等的裂缝和塌陷范围,其电性特征是视电阻率值变化幅度大,呈不规则状,分辨率较低;对于以巷道式开采为主的煤矿古采空区,由于采空区内充填物复杂,其视电阻率值可高于、也可低于正常地层的电阻率,在解释上要加以注意。然后,总结出了采空区未塌陷和完全塌陷的地电模型并对该模型进行正演计算,分别对瞬变电磁法在探测高阻采空区和低阻采空区的异常反应能力进行了探讨。同时较详细的分析了瞬变电磁法在探测煤田采空区的深度和精度问题。最后,以重点工区的应用成果为例,阐述了该方法技术的有效性。结合工作实践总结了瞬变电磁法在探测煤田采空区的优点及注意事项,并就我们目前的应用现状,以及国内外的发展对该方法做出了展望。更多还原

【Abstract】 In coal mine production, the exploitation of coal seam makes more mined-out areas, the collapse of which will make the ground sink and split, devastate the infield and buildings, and destroy the ecological environments. Hence, it is significant to use geophysical methods efficiently and economically to survey and evaluate the mined-out areas and give feasible control measures. In the latest years, many geophysicists have done research on the subjects and make a lot of practical findings. But as a whole, the research of the survey of mined-out areas is still in a developing stage, and the principles and the means of the survey are faulty. The successful experience and data accumulation on the research in China and aboard mainly include collecting data, investigating and visiting, drilling, experiments indoor and numerical simulation.Firstly , it simply introduces the developed general situation and working arrays of Transient Electromagnetic Methods, it also summarizes its main advantages. And it detailed analyzes the characteristics of symmetric semi-space, layered telluric medium of TransientElectromagnetic Methods, deduces apparent resistivity(ρ_τ) formulae of earlier, later andwhole stage channels, it also analyzes and deduces the TEM response effect of local conductive body in high resistance medium and its apparent resistivity formula, inquires into the causing reason, distinguishing method and the way of eliminating or reducing its effect of TEM additional effects. It summarizes the characteristics of physical simulated profiling anomaly of common loop point array. By analyzing some main factors which affecting the observation of TEM, it discusses the way of reducing geological noise, it affirms the relationship between the side length of loop and depth of prospecting, current of supply electricity and the radio of signal and noise.Secondly, the paper discusses the connection between different kind of underground gob from excavating coal of different manner and terra electricity speciality. It thinks that colliery gob of high extent mechanization destroys its overcast terrane badly, the amount of crack is excessive and the acreage of sinkage is large. The characteristic of terra electricity is high parallactic resistivity value, large-scale distributing, obvious lave aid facile distinguishing. However, colliery gob of low extent mechanization or nonstandard exploration less destroys its overcast terrane, but it can also form different scale of crack and the acreage of sinkage. The characteristic of terra electricity is low parallactic resistivity value, small-scale distributing, abnormal law and discommodiousness distinguishing; for colliery old gob mined mainly through laneway, because of its involuted filling, the parallactic resistivity value may be higher or lower than resistivity value of normal terrane. It calls for especial notice in explaining.Then, goaf not completely collapse and the collapse of the theoretical model as well as theoretical model is my calculation, respectively transient electromagnetic method in the detection of high resistivity goaf and low resistivity goaf abnormal response capabilities were discussed. While more detailed analysis of transient electromagnetic method in the detection of coal gob of depth and precision.Finally, focus on the kinds of application of the results as an example to illustrate the effectiveness of the method. Practice conjunction with the work of transient electromagnetic method in the detection of coal goaf and the merits attention, and our current application status at home and abroad, and the development of the method to make the prospect.更多还原