沿空留巷切顶卸压作用机理研究

发布时间：2018-03-18 12:04

  本文选题：沿空留巷　切入点：坚硬顶板　出处：《安徽理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：切顶卸压手段在解决坚硬顶板下留巷困难问题方面独树一帜,本文以潘一东矿1252(1)工作面为研究背景,采用相似模拟、数值模拟、理论分析、工业实测等方法,深入探讨了切顶卸压在坚硬顶板下留巷的作用机理。采用相似模拟手段形象再现了切顶与否,在沿空留巷巷道开挖、开挖稳定、一次开挖、一次开挖稳定、二次开挖五个时期中巷道围岩及应力变化情况。对比分析切顶与否在五个时期围岩应力及岩层垮落变化的不同,得出切顶在后三个时期的作用比较明显,其改变了硬岩层跨断方式,防止采空区大面积悬顶后,突然下沉而产生巨大载荷,可有效缓解巷旁支护阻力压力集中问题。运用数值模拟手段进一步对比分析切顶与否围岩应力场及位移场的变化,进一步证明切顶后可缓解围岩变形过大,墙体应力集中等问题。同时,模拟分析在不同切顶高度、不同切顶角度、不同采高条件下,巷道围岩应力及位移的变化趋势,并针对1252(1)工作面提出了最优切顶角度35°,最优切顶高度20m,这与实践相一致。在采用相似模拟、数值模拟分析的基础上,运用理论手段以冒落带内综合强度30MPa为临界值,判定其是否可自行冒落并能否充填满采空区为一依据;以裂隙带内是否存在关键层作为另一依据,参照这两依据将顶板划分为4类岩层。结合1252(1)工作面实际地质条件判定其属于第Ⅱ类岩层。以第Ⅱ类岩层为基础,建立结构力学模型,分析顶板极限垮落层位高度以及冒落带高度,推导出关键块体B破断时特征长度与厚度。建立Ⅱ类岩层留巷力学模型,推导出巷旁临界支护阻力公式,得出支护阻力与悬顶距X2成正比,并采用敏感性分析手段,得出块体B特征长度L与悬顶距对巷旁支护阻力影响较大,针敏感度较大参数,提出Ⅱ类覆岩结构下巷道的维护措施。在工程实践中运用上述分析的巷道维护手段,通过现场位移应力实测以及巷道维护实照的拍摄,切实有效的表明,运用切顶卸压手段可弱化坚硬顶板下来压集中问题,减少巷道围岩移近量,有效保护巷道完整性,保证坚硬顶板下留巷成功。
[Abstract]:The method of roof cutting and pressure relief is unique in solving the difficult problem of retaining roadway under hard roof. In this paper, taking the 1252DU 1 face of Panyidong Mine as the research background, similar simulation, numerical simulation, theoretical analysis, industrial measurement and so on are adopted. In this paper, the mechanism of cutting pressure relief under hard roof is deeply discussed. The similar simulation method is used to reproduce the roof cutting or not, and the roadway along the goaf is excavated, the excavation is stable, the first excavation is stable, the first excavation is stable, the first excavation is stable, the other is the stability of the excavation. The change of surrounding rock and stress of roadway during the five periods of secondary excavation, the difference of stress of surrounding rock and rock collapse in five periods of roof cutting or not is analyzed, and it is concluded that the effect of roof cutting in the latter three periods is obvious. It has changed the hard rock stratum span and broken way, preventing the huge load after the large area suspended roof of the goaf, suddenly sinking and producing the huge load. The stress field and displacement field of surrounding rock in roof cutting or not are further compared and analyzed by numerical simulation. It is further proved that the deformation of surrounding rock can be alleviated after roof cutting. At the same time, the variation trend of surrounding rock stress and displacement of roadway under different roof cutting height, different cutting angle and different mining height is simulated. The optimum roof cutting angle 35 掳and the optimum cutting height 20 m are put forward for 1252Q1) working face, which is consistent with practice. On the basis of similar simulation and numerical simulation analysis, the critical value is 30 MPA in the caving zone by theoretical means. It is determined whether it can caving on its own and whether it can fill up the goaf, and whether there is a critical layer in the fissure zone as another basis, According to these two bases, the roof is divided into four types of rock formations, combined with the actual geological conditions of 1252Q1) face, it is determined that it belongs to the second type rock stratum. Based on the second type rock stratum, the structural mechanics model is established. Based on the analysis of the height of roof limit collapse and the height of caving zone, the characteristic length and thickness of key block B are deduced. The mechanical model of retaining roadway of type 鈪，

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