探地雷达在采煤工作面上保护层检测中的应用

发布时间：2018-05-13 17:23

本文选题：探地雷达 + 上保护层厚度检测　；参考：《西安科技大学》2016年硕士论文

【摘要】：智能化煤矿综采工作面要求采煤机在工作时能够根据开采环境自动调节滚筒的高度,而滚筒高度的自动调节首先需要进行上保护层厚度检测和煤岩界面识别,因此采煤工作面上保护层检测对于智能机械化采煤具有重要意义。论文分析了主流煤岩界面探测技术的特点,总结出探地雷达最适于留煤厚型开采方式的煤岩界面识别。在研究了煤层中探地雷达信号损耗特性的基础上,仿真分析了煤层中电磁波相速度、衰减系数与频率的关系,为探地雷达应用于煤层探测时中心频率的选择以及相速度、路径损耗计算方法的选择提供依据。根据采煤工作面中的信号特征,建立了上保护层探测模型,研究了采煤机附近混合气体介电常数以及衰减常数的计算方法,利用电磁波在探测上保护煤层时的路径损耗以及在介质分界面上的反射特性得到了基于电波损耗特性的保护煤层厚度计算方法并提出了一种上保护层覆岩识别算法。对采煤工作面中不同情形下的覆岩识别进行了仿真分析,仿真结果表明了算法的有效性以及采煤机附近混合气体介电特性研究的必要性。为了提高采煤工作面探地雷达回波数据的解释准确度,采用时域有限差分方法(FDTD)进行了探地雷达正演模拟,并以二维FDTD仿真为例,对不同层厚的完全匹配层(PML)吸收边界条件的吸收效果进行了仿真分析,为FDTD算法进行正演仿真时吸收边界条件的设置奠定基础。分别实现了探地雷达在上保护煤层中的厚度检测、简单地质构造、煤层中的异常水体和空洞、褶皱煤层以及煤层中常见的破碎带、富水破碎带问题的正演模拟,总结出了各自的探地雷达剖面图特征,为煤层中实际探测目标体的识别和探地雷达成像资料的研究提供了依据。
[Abstract]:The intelligent fully mechanized coal mining face requires that the shearer can automatically adjust the height of the roller according to the mining environment, and the automatic adjustment of the height of the roller requires the detection of the thickness of the upper protective layer and the identification of the coal and rock interface. Therefore, it is important for intelligent mechanized coal mining to detect the protective layer on the mining face. This paper analyzes the characteristics of the mainstream coal-rock interface detection technology, and concludes that GPR is most suitable for coal-rock interface recognition. On the basis of studying the characteristics of signal loss of ground penetrating radar in coal seam, the relationship among phase velocity, attenuation coefficient and frequency of electromagnetic wave in coal seam is simulated and analyzed. In order to select the center frequency and phase velocity when ground penetrating radar is used in coal seam detection, The selection of path loss calculation method provides the basis. According to the signal characteristics of coal mining face, the detection model of upper protective layer is established, and the calculation method of dielectric constant and attenuation constant of mixed gas near shearer is studied. A method for calculating the thickness of protective coal seam based on the characteristics of electromagnetic wave loss is obtained by using the path loss of electromagnetic wave to protect the coal seam and the reflection characteristics on the dielectric interface, and an algorithm for identifying the overburden of the upper protective layer is proposed. The simulation analysis of overburden recognition in different situations in coal mining face shows the validity of the algorithm and the necessity of studying the dielectric characteristics of mixed gas near the shearer. In order to improve the interpretation accuracy of ground penetrating radar echo data in coal mining face, the forward simulation of ground penetrating radar is carried out by using FDTD (finite difference time domain) method, and the two-dimensional FDTD simulation is taken as an example. The absorption effect of perfectly matched laminar (FDTD) absorbing boundary conditions with different thickness is simulated and analyzed, which lays a foundation for the setting of absorbing boundary conditions in the forward simulation of FDTD algorithm. The forward modeling of the thickness detection of the ground penetrating radar in the upper protective coal seam, the simple geological structure, the abnormal water body and cavity in the coal seam, the folded coal seam and the common broken zone in the coal seam, and the problem of the water-rich broken zone are realized, respectively. The characteristics of their respective GPR profiles are summarized, which provides a basis for the recognition of actual detection objects in coal seam and the study of GPR imaging data.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD67

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