特厚煤层软弱底板沿空巷道超前支护段稳定性研究

发布时间：2018-02-05 02:52

本文关键词： 软底超前支护段超前支架底板比压数值模拟　出处：《安徽理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：针对目前沿空巷道软弱底板超前支架易出现钻底和移架困难、巷道围岩变形量大、锚杆弹出及折断等问题,以水帘洞煤矿特厚煤层采场超前支架稳定性控制为工程背景,开展了ZF3802沿空巷道超前支护段围岩稳定性控制研究。本文在详细分析前人研究成果的基础上,运用理论分析、数值模拟与工程实践相结合的方法,研究了底煤厚度对超前支架稳定性的影响,而超前支架的稳定性直接影响超前支护段的稳定性,因此,底煤厚度间接影响了巷道超前支护段围岩稳定性。基于矿压理论,详细研究了顶板运动规律,并对动压进行分析；通过建立“支架—围岩”结构力学模型,分别计算出一般情况下和最危险情况即老顶切落条件下超前支架压力,最终得出超前支架合理支护强度应不小于0.73MPa而不大于0.93MPa。通过理论分析、现场测试等研究方法,得出了底煤厚度与底板比压之间的规律,整体呈“S”型曲线分布；通过分析超前支架底座的结构力学特点,得出了超前支架底座比压分布特性,呈梯形或三角形分布,计算得出底座接触比压最大值为6.81MPa,基于支架不发生钻底的条件,得出理论上应该留设的底煤厚度为2.2m。运用FLAC3D软件研究底煤厚度分别为0.5m、1.0m....3.5m时,得出距离ZF3802工作面不同位置的应力云图及顶板受力曲线。通过对比分析距离工作面前方和后方30m范围内顶板垂直应力图得知,底煤厚度大于等于2.5m时,巷道围岩整体受力较小,支承压力峰值距离沿空巷道较远,最利于巷道超前支护段围岩稳定。通过理论研究及现场实践,总结了一套巷道内回收底煤的工艺。该工艺在水帘洞煤矿成功实施,不仅可以增加巷道净高,而且能够提高煤炭回采率。工程实践表明,巷道底煤厚度小于2.5m时,巷道顶底板移近量和两帮变形量较大,超前支架发生多次钻底严重的情况,无法顺利移架,严重影响了工作面的正常推采,且不利于超前护段围岩稳定；巷道底煤厚度大于等于2.5m时,顶底板移近量、两帮变形量及超前支架前后端钻底量较小,且超前支架承载稳定,能够顺利移架,利于围岩稳定。综上所述,通过理论计算得出的留设底煤厚度应不小于2.2m,结合现场工程应用情况,最终确定最佳留设底煤厚度为2.5m。
[Abstract]:Aiming at the problems such as the difficulty of drilling bottom and moving frame, the large deformation of surrounding rock, the bolt ejection and breaking, etc, the leading support of weak floor plate in goaf roadway is easy to appear at present. The background of the project is the stability control of the stope leading support in the very thick coal seam of Shuishendong coal mine. The stability control of surrounding rock in advance support section of ZF3802 goaf roadway is studied. Based on the detailed analysis of previous research results, the method of combining theoretical analysis, numerical simulation and engineering practice is used in this paper. The influence of bottom coal thickness on the stability of advance support is studied, and the stability of leading support is directly affected by the stability of leading support. Therefore, the thickness of bottom coal indirectly affects the stability of surrounding rock in advance support of roadway. Based on the theory of rock pressure, the law of roof motion is studied in detail, and the dynamic pressure is analyzed. By establishing the structural mechanics model of "brace-surrounding rock", the leading support pressure is calculated under the general and the most dangerous conditions, that is, the cutting and falling condition of the main roof. Finally, it is concluded that the reasonable support strength of leading support should not be less than 0.73 MPA but not greater than 0.93MPa. Through theoretical analysis, field test and other research methods, the law between the thickness of bottom coal and the specific pressure of floor is obtained, and the whole distribution of the curve is "S". By analyzing the structural mechanical characteristics of the lead support base, the specific pressure distribution characteristics of the lead support base are obtained, which are trapezoid or triangular distribution, and the maximum contact specific pressure of the base is 6.81 MPA. Based on the condition that the support does not drill bottom, the thickness of bottom coal that should be set up theoretically is 2.2 m. The FLAC3D software was used to study the thickness of bottom coal when the thickness of coal was 0.5 m, 1.0m...3.5m, respectively. The stress cloud map and roof stress curve of different positions from ZF3802 face are obtained, and the vertical stress diagram of roof in 30m range from the front and rear of the face is obtained by comparing and analyzing the stress curve of roof. When the thickness of bottom coal is more than 2.5 m, the overall stress of surrounding rock of roadway is small, and the peak value of supporting pressure is far away from the goaf roadway, which is most favorable to the stability of surrounding rock in advance support section of roadway. Through theoretical research and field practice, this paper summarizes a set of technology of recovering bottom coal in roadway, which has been successfully implemented in Shuishendong coal mine, and can not only increase the net height of roadway. The engineering practice shows that when the coal thickness of roadway bottom is less than 2.5 m, the roof and floor displacement and deformation of two sides of roadway are larger, and the serious condition of multiple drilling bottom occurs in advance support. The failure to move the frame smoothly has seriously affected the normal pushing and mining of the working face and is not conducive to the stability of the surrounding rock in the advance protection section; When the coal thickness of roadway bottom is more than 2.5 m, the roof and floor plate move closer, the deformation of two sides and the amount of end drilling bottom before and after the leading support are smaller, and the load bearing of the leading support is stable, and it can move the frame smoothly. In summary, the thickness of the coal left behind should be not less than 2.2 m by theoretical calculation, and the best thickness of the coal is determined to be 2.5 m in combination with the field engineering application.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD353

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