近距离煤层采空区下大采高综采面覆岩活动规律研究

发布时间：2018-06-13 20:26

本文选题：矿山压力 + 覆岩移动　；参考：《辽宁工程技术大学》2015年硕士论文

【摘要】：近距离煤层下行开采时,下位煤层顶板受上煤层开采时超前支撑压力、采后解压以及采空区重新压实的影响,不再完整,上位覆岩结构也由原来的完整岩层变为垮落、断裂岩层,因此岩层移动和矿压显现将有别于单一煤层开采时的情况。论文综合运用相似材料模拟,理论分析和现场监测的方法研究近距离煤层下行开采时覆岩移动和矿压显现规律。首先根据测得的岩石物理力学参数搭建相似材料模型,布设测点,然后依次完成了903、904和1103工作面的开挖模拟工作,在开挖过程中运用数字图像相关法记录测点位移数据。然后对测点位移数据进行聚类分析,得出受采动影响的垮落带、裂隙带和弯曲下沉带的范围。分析来压规律,得出下煤层开采时初次来压步距小于上煤层,周期来压步距平均值小于上煤层,岩层断裂线多位于工作面的前方。分析测点位移特点,得出下煤层开采时最大位移点滞后工作面的距离小于上煤层开采的滞后距离；单位采高对应的覆岩下沉量大于上煤层开采时的对应值；岩层移动存在外包络线,最外侧为关键层的位置。分析离层发育,得出下煤层开采时,水平方向离层率呈双驼峰状,峰值点处相对上煤层开采时变大,而采空区中部离层率相对上煤层开采时变小；竖直方向离层率曲线呈两峰三谷的双驼峰状,关键层位于峰值点右侧的波谷区域。分析关键层位置,得出下煤层开采时关键层位置上移。通过对来压规律和覆岩移动规律的分析,提出了近距离煤层下位煤层开采时“块体-散体-内压力拱-砌体梁-外压力拱”覆岩结构模型,分析了各部分对矿压显现的影响；建立岩层断裂线处离层发育模型,分析了离层厚度的影响因素。最后结合现场监测,得出1103工作面9煤采空区下初次来压步距平均值48.2m,周期来压步距平均值18.6m,与相似材料模拟所得结论基本吻合。
[Abstract]:In the downgoing mining of close distance coal seam, the roof of the lower coal seam is no longer intact due to the influence of the leading supporting pressure, the decompression after mining and the re-compaction of the goaf during the mining of the upper coal seam, and the upper overburden rock structure has also changed from the original intact rock layer to the collapse. Fault strata, therefore, strata movement and rock pressure behavior will be different from the single coal seam mining situation. In this paper, similar material simulation, theoretical analysis and field monitoring are used to study the overburden movement and rock pressure behavior in the downlink mining of coal seam. The similar material model was built according to the measured rock physical and mechanical parameters and the measuring points were set up. Then the excavation simulation of 903904 and 1103 working faces was completed in turn. The displacement data of measured points were recorded by digital image correlation method in the excavation process. Then, the range of collapse zone, crack zone and bending subsidence zone affected by mining movement is obtained by cluster analysis of displacement data of measured points. By analyzing the law of coming pressure, it is concluded that the initial pressure step distance is smaller than the upper coal seam, the average value of the periodic pressure step distance is less than the upper coal seam, and the rock seam fracture line is mostly located in the front of the working face. By analyzing the displacement characteristics of the measuring points, it is concluded that the distance of the maximum displacement point lag face is smaller than that of the upper coal seam mining, the overburden subsidence corresponding to the unit mining height is larger than the corresponding value of the upper coal seam mining. Strata movement exists outer envelope, the outermost is the position of key layer. By analyzing the development of the separation layer, it is concluded that in the mining of the lower coal seam, the horizontal separation rate is like a double hump, the mining time varying at the peak point is larger than that in the upper coal seam, while in the middle of the goaf, the separation rate is smaller than that in the upper coal seam mining. The vertical separation rate curve is a double hump with two peaks and three valleys, and the key layer is located in the valley area to the right of the peak point. By analyzing the position of the key layer, it is concluded that the position of the key layer moves up when mining the coal seam. Based on the analysis of the law of pressure coming and the law of overburden movement, this paper puts forward the overburden structure model of "block-bulk-internal pressure arch-masonry beam-external pressure arch" when mining the coal seam in the lower position of short distance coal seam, and analyzes the influence of each part on the rock pressure behavior. The development model of dissociation layer at fault line is established, and the factors influencing the thickness of separated layer are analyzed. Finally, combined with field monitoring, it is obtained that the average initial pressure step distance is 48.2 m and the periodic pressure step distance is 18.6 m under the 9 coal goaf of 1103 working face, which is basically consistent with the conclusion obtained by similar material simulation.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD325;TD823.81

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