极近距离煤层开采巷道支护技术研究

发布时间：2018-06-05 18:30

本文选题：极近距离煤层 + 长壁采空区下　；参考：《太原理工大学》2016年硕士论文

【摘要】：极近距离煤层开采条件下,由于煤层间距极小,下煤层开采前顶板的完整性已受到上覆煤层开采的损伤破坏,导致下煤层回采巷道维护困难,其控制原理和支护方案的合理确定仍是一个难题。下煤层开采时围岩的稳定性与上煤层开采的影响程度密切相关,如果上煤层的开采方式不同,下煤层开采时顶板的整体力学环境也就不同,如当上煤层采用长壁全部垮落法开采时,下煤层开采时的顶板为上煤层开采而遭到损伤的层间岩层和上煤层开采已垮落的矸石,下煤层开采时的顶板边界条件为散体边界条件;若上煤层开采为刀柱式采煤法,上煤层开采后采空区残留的诸多煤柱在底板形成集中压力,下煤层开采时的顶板边界条件为集中载荷边界条件。不同的边界条件下,必然使下煤层开采的矿山压力显现呈现出多样性。本文分别对三泉矿长壁采空区下极近距离煤层开采条件、王封矿刀柱采空区下极近距离煤层开采条件,运用理论分析、数值模拟、现场实测的方法进行了巷道支护方面的研究。主要研究成果如下:(1)研究了三泉矿长壁工作面开采煤柱稳定性和煤柱载荷在底板煤岩层中的应力分布规律;理论分析了巷道在非均匀应力场中,支护体结构更易出现局部过载,产生局部破坏,最终可能导致支护体结构失稳的原因;计算确定出了下煤层回采巷道合理内错距离。(2)运用弹塑性理论、滑移线场理论计算出上煤层开采后底板破坏深度范围,并据此将三泉矿11号煤层巷道顶板分为三种类型:破碎松散顶板类型、裂隙较发育顶板类型以及普通顶板类型,最后将三泉矿11号煤层巷道分段支护范围定为:小于2m的巷道、2-4m的巷道与4m以上的巷道,对这三种层间距的巷道分段进行支护并通过现场实践进行验证。(3)对王封矿8号煤层刀柱群下巷道围岩应力条件进行分析得出:刀柱群下巷道顶板压力分布是呈波动性交替变化特征,研究了刀柱采空区下巷道围岩应力条件并对支架进行力学性能分析;刀柱群下巷道围岩变形与破坏程度表现出极强的位置相关性:①位于煤柱下方的煤岩层近似承受以垂直应力为最大主应力,水平应力为最小主应力的压应力场;②位于采空区下方的煤岩层近似承受以水平应力为最大主应力,垂直应力为最小主应力的压应力场。(4)王封矿8、9号煤层层间距仅为0.75m,在此条件下,顶板松散破碎,极易冒、漏顶,使用锚杆难以进行围岩加固,只能采用金属支架。通过分析不同位置处巷道围岩的破坏机理和失稳破坏特征,结合支架力学性能分析提出了相应的巷道围岩稳定性控制对策。上述研究成果均在实践中取得了较好的效果,对类似条件下巷道的围岩稳定性控制具有一定的借鉴及参考价值。
[Abstract]:Under the condition of extremely close coal seam mining, the integrity of the roof is damaged and damaged by the overlying coal seam mining before the coal seam mining, which leads to the difficult maintenance of the mining roadway in the lower coal seam. Its control principle and the rational support scheme are still a difficult problem. The stability of the surrounding rock and the coal seam mining in the coal seam mining are still a difficult problem. The influence degree is closely related. If the mining mode of the upper coal seam is different, the overall mechanical environment of the roof is different when the lower coal seam is mined, for example, when the upper coal seam is exploited by the long wall full caving method, the roof of the lower seam mining is damaged by the upper seam mining and the broken coal mine is mined, and the lower coal seam is mined. The boundary conditions at the top of the roof are scattered boundary conditions. If the upper coal seam mining is a knife pillar mining method, many coal pillars remaining in the goaf after the upper coal seam mining will form the concentrated pressure, and the roof boundary condition of the lower coal seam mining is the concentrated load boundary condition. Under the different boundary bars, the mining pressure of the lower coal seam will inevitably appear. The main research results are as follows: (1) the main research results are as follows: (1) the work of the long wall work of the three springs is studied. The stress distribution law of the stability of coal pillar and the load of coal pillar in the coal rock strata of the floor is opened. In the nonuniform stress field of the roadway, it is theoretically analyzed that the support structure is more prone to partial overload and local damage, which may eventually lead to the instability of the structure of the supporting body, and the reasonable internal error distance of the mining roadway in the lower coal seam is determined. (2) Based on the theory of elastoplastic and slip line field, the failure depth range of the bottom floor after the coal seam mining is calculated. According to this, the roof of the No. 11 seam roadway of the three spring mine is divided into three types: the type of broken loose roof, the type of roof and the common roof type. Finally, the subsection support range of the No. 11 seam roadway of the three spring mine is determined to be less than 2 M laneway, 2-4m roadway and 4m above roadway, support the three layers of roadway segment and verify through field practice. (3) analysis of the stress conditions of the surrounding rock of the roadway group under the No. 8 coal seam of Wang Feng mine, the distribution of the roof pressure distribution under the knife column group is the characteristic of fluctuating intercourse, and the goaf of the knife column is studied. The stress conditions of the surrounding rock and the mechanical properties of the support are analyzed. The deformation and damage degree of the surrounding rock under the knife column group shows a very strong position correlation: (1) the coal rock under the coal pillar is approximately subjected to the vertical stress as the maximum principal stress and the horizontal stress is the minimum main stress stress field; The coal rock stratum is approximately bearing the maximum principal stress with the horizontal stress as the maximum principal stress and the vertical stress is the minimum main stress stress field. (4) the interval between the coal seam layer 8,9 of Wang Feng mine is only 0.75m. Under this condition, the roof is loose and broken, it is very easy to take the roof, and it is difficult to reinforce the surrounding rock with the bolt. On the basis of the failure mechanism and the characteristics of instability and failure, the corresponding control measures for the stability of the roadway surrounding rock are put forward in combination with the analysis of the mechanical properties of the support. All of these results have achieved good results in practice, and have certain reference and reference value for the stability control of the surrounding rock under similar conditions.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD353

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