遇水前后煌斑岩声发射特性及其对特厚煤层综放开采覆岩运移的影响

发布时间：2019-05-18 20:38

【摘要】：随着煤炭资源开采强度的提高，特厚煤层的开采已经在全国许多地区纷纷展开，但是在山西的大同、朔州、淮南、江苏的徐州（如张集煤矿）、山东的枣庄（如山家林煤矿）等很多矿区都出现了煌斑岩顺层大面积侵入煤岩层的现象。其中以塔山矿区尤为突出，煌斑岩的侵入不仅导致局部煤层的性质发生了物理化学变化，使煤的价值降低，更为重要的是煌斑岩的侵入导致井下各种巷道的布置、回采方式、顶底板的维护方式都发生了很大的变化。比如在塔山矿8102工作面，由于煌斑岩的侵入，按传统的矿压理论选取的支架工作阻力提高到13000KN后仍发生多次压架现象。同时在现场中发现，地下水会导致煌斑岩的强度有明显的降低，而煌斑岩的强度对覆岩运移有很大的影响。对于这种特殊地质条件下的特厚煤层综放开采，尚没有成熟的理论作指导，也没有现成的经验可借鉴，因此急需相关的基础理论指导生产实践。声发射技术能很好的监测煤矿坚硬顶板稳定性，通过声发射特征来预报来压情况及动力灾害。但是，目前这方面的研究成果很少。因此，研究遇水前后煌斑岩声发射特性及其对特厚煤层综放开采覆岩运移的影响很有意义。 本文以大同塔山矿煌斑岩侵入条件下特厚煤层综放开采作为研究背景，从采场覆岩移动规律着手，通过力学实验和声发射实验，对三种不同含水状态煌斑岩的力学特性和声发射特征进行研究，通过物理相似模拟与数值模拟相结合的方法对遇水前后煌斑岩层状侵入条件下特厚煤层综放开采的采场覆岩移动变形规律进行了研究，具体研究内容如下： （1）通过对煌斑岩进行常规单轴压缩条件下的声发射试验，分析煌斑岩的声发射特征；通过三种含水状态煌斑岩在单轴循环加卸载过程中的声发射实验，分析声发射各参数与应力应变的关系，分析煌斑岩声发射Felicity效应，分析水对煌斑岩的声发射特征的影响。研究表明水对煌斑岩的力学性质、声发射特性、Felicity效应都有一定的影响。 （2）通过物理相似模拟试验的基础研究，分析遇水前后两种状态煌斑岩层状侵入条件下特厚煤层综放开采上覆岩层的垮落特征。结果表明自然状态煌斑岩侵入条件下开采到88.5m时发生初次来压，周期来压步距约为13.5m~16.5m；遇水煌斑岩侵入条件下开采到50m时发生初次来压，周期来压步距约为8m~10m。 （3）通过UDEC数值模拟，分析遇水前后两种状态煌斑岩层状侵入条件下特厚煤层综放开采上覆岩应力分布规律、移动变形规律与岩层垮落特征。结果表明煌斑岩遇水之后，初次来压步距减小，，工作面推进相同的距离，支承应力的峰值变大。 （4）根据上述相似模拟分析与数值模拟的结果，分析煌斑岩层状侵入条件下特厚煤层综放开采上覆岩层移动变形的力学特性，建立煌斑岩层状大面积侵入条件下特厚煤层综放开采上覆控制层运移的力学模型。
[Abstract]:With the improvement of coal resources mining intensity, the mining of extra thick coal seams has been carried out in many areas of the country, but in Datong, Shuozhou, Huainan and Xuzhou in Jiangsu Province (such as Zhangji Coal Mine), In Zaozhuang (such as Shanjialin Coal Mine) in Shandong Province, there is a large area invasion of lamprophyre bedding into coal strata. Especially in Tashan mining area, lamprophyre intrusion not only leads to physical and chemical changes in the properties of local coal seams and reduces the value of coal, but also leads to the layout and mining mode of various underground roadway caused by lamprophyre intrusion. Great changes have taken place in the maintenance mode of the top and bottom plate. For example, in 8102 working face of Tashan Mine, due to the invasion of lamprophyre, the working resistance of the support selected according to the traditional mine pressure theory is increased to 13000KN. At the same time, it is found that groundwater will lead to a significant decrease in the strength of lamprophyres, and the strength of lamprophyres has a great influence on the migration of overlying rocks. There is no mature theory and ready-made experience to guide the fully mechanized caving mining of ultra-thick coal seam under this special geological condition, so it is urgent to guide the production practice with the relevant basic theory. Acoustic emission technology can monitor the stability of hard roof in coal mine, and predict the pressure and dynamic disasters through the characteristics of acoustic emission. However, at present, there are few research results in this field. Therefore, it is of great significance to study the acoustic emission characteristics of lamprophyre before and after water encounter and its influence on overlying rock migration in fully mechanized top coal caving mining in ultra-thick coal seam. In this paper, based on the research background of fully mechanized top coal caving mining in ultra-thick coal seam under the condition of overlying rock intrusion in Datong Tashan Mine, starting from the movement law of overlying rock in stope, the mechanical experiment and acoustic emission experiment are carried out. The mechanical properties and acoustic emission characteristics of three different water-bearing lamprophyres were studied. The movement and deformation of overlying rock in fully mechanized caving mining of super thick coal seam under the condition of lamprophyre rock intrusion before and after water encounter is studied by means of physical similarity simulation and numerical simulation. The specific research contents are as follows: (1) through the acoustic emission test of lamprophyre under conventional uniaxial compression, the acoustic emission characteristics of lamprophyre are analyzed; Based on the acoustic emission experiments of three kinds of water-bearing lamprophyres during uniaxial cyclic loading and unloading, the relationship between acoustic emission parameters and stress and strain is analyzed, the Felicity effect of lamprophyre acoustic emission is analyzed, and the influence of water on the acoustic emission characteristics of lamprophyres is analyzed. The results show that water has certain effects on the mechanical properties, acoustic emission characteristics and Felicity effect of lamprophyres. (2) through the basic research of physical similarity simulation test, the collapse characteristics of overlying strata in ultra-thick coal seam under the condition of lamprophyre rock intrusion before and after water encounter are analyzed. The results show that the first pressure occurs when the lamprophyre intrusions in the natural state reach 88.5m, and the periodic pressure step distance is about 13.5 m 鈮

本文编号：2480319