浅埋煤层大采高综采面区段煤柱宽度留设理论及试验研究

发布时间：2018-10-19 07:46

【摘要】：浅埋煤层大采高综采面区段煤柱合理宽度对保证顺槽稳定性、提高回采率具有重要工程价值和意义。本文以陕北某煤矿5-2煤浅埋煤层为工程背景,通过现场监测、理论计算和数值模拟相结合的方法,开展浅埋煤层大采高工作面区段煤柱留设宽度研究。本文的主要结论有:(1)通过室内试验,得到煤岩体基本物理力学参数;分析了浅埋煤层综采面区段煤柱留设合理宽度的主要影响因素;得到了区段煤柱内部的应力分布特征;根据工作面条件,建立了区段煤柱的压杆受力模型,并对煤柱挠度进行了分析;在分析区段煤柱工作状态的基础上,得到了区段煤柱保持稳定的基本条件。(2)对原有的19.2m区段煤柱进行现场监测可知,在一次和二次采动影响下,围岩变形量不超过30mm,煤柱的内部比较完整、裂隙及破碎区较少,回采影响下的区段煤柱支承能力较高,有必要对区段煤柱宽度进行优化设计。(3)基于弹塑性极限平衡理论,建立力学模型,将区段煤柱内的塑性区和弹性区的竖向应力分布按照二次曲线进行研究,得到该煤矿浅埋煤层大采高长壁综采工作面区段煤柱宽度理论计算公式,通过该公式计算得到区段煤柱宽度不应小于15.18m。FLAC数值模拟结果表明,当区段煤柱宽度处于15~17m时,其内部的塑性区范围合理、弹性区宽度满足要求。综上,建议将区段煤柱宽度确定为15.7m。(4)对矿方优化后17.45m的区段煤柱进行现场工业试验,得到优化后煤柱两侧的松动圈范围分别为1.35m左右和0.6m左右;优化后的区段煤柱两侧塑性区不超过2m,弹性区宽度为14.75m,优化后的区段煤柱具有足够的稳定性,优化后17.45m的区段煤柱宽度合理可行。
[Abstract]:The reasonable width of pillar in fully mechanized mining face section with large mining height in shallow coal seam is of great engineering value and significance to ensure the stability of trench and to improve the recovery rate. In this paper, based on the engineering background of 5-2 shallow coal seam in a coal mine in northern Shaanxi, through the combination of field monitoring, theoretical calculation and numerical simulation, the study on the width of coal pillar in the section of large mining height working face of shallow buried coal seam is carried out. The main conclusions of this paper are as follows: (1) through laboratory tests, the basic physical and mechanical parameters of coal and rock mass are obtained, the main factors influencing the reasonable width of pillar in fully mechanized face section of shallow coal seam are analyzed, and the stress distribution characteristics of pillar in the section are obtained. According to the condition of the coal face, the stress model of the pillar is established, and the deflection of the pillar is analyzed, on the basis of the analysis of the working state of the pillar in the section, The basic conditions of maintaining the stability of the section pillar are obtained. (2) the site monitoring of the original section 19.2m pillar shows that under the influence of primary and secondary mining, the deformation of surrounding rock is not more than 30mm, the inner part of the pillar is relatively complete, and the fracture and broken area are less. Under the influence of mining, the bearing capacity of coal pillar is high, so it is necessary to optimize the width of pillar. (3) based on the theory of elastoplastic limit equilibrium, a mechanical model is established. The vertical stress distribution in the plastic and elastic areas of the coal pillar is studied according to the quadratic curve, and the theoretical formula for calculating the width of the pillar in the section of the long wall fully mechanized mining face with large mining height in the shallow coal seam is obtained. The results of numerical simulation show that when the width of coal pillar is 15m, the range of plastic zone is reasonable and the width of elastic zone meets the requirement. In summary, it is suggested that the width of the section pillar should be determined to be 15.7m. (4) the field industrial test of the section pillar at 17.45m after optimization is carried out, and the range of loose circles on both sides of the optimized coal pillar is about 1.35m and 0.6m respectively. The plastic zone on both sides of the optimized section is less than 2 m and the width of the elastic zone is 14.75 m. The optimized section pillar has enough stability and the width of the optimized section of 17.45 m coal pillar is reasonable and feasible.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD822.3

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