浅埋煤层间隔式空区下长壁综采覆岩移动规律研究

发布时间：2018-10-15 17:54

【摘要】：针对南梁煤矿2-2#煤层间隔式开采工艺、上下组煤层层间距、岩性、地貌特征等参数研究下组煤基本顶运动规律,综合采用现场调研、实验室实验、理论计算、数值模拟、现场实测分析等方法,对浅埋冲沟地貌间隔式煤柱下方集中应力传递规律、间隔式煤柱及采空区下回采顶板运动、支架合理阻力,基本顶破断方式及规律进行结构化、系统性分析,主要研究成果如下:(1)依据南梁煤矿地貌特征将地表分为平缓地貌与冲沟地貌,分别分析两种地貌下煤柱上覆载荷分布规律,通过数值模拟,现场观测及理论计算分析不同地貌条件下煤柱上覆法向载荷,其中冲沟地貌间隔式煤柱上覆线性载荷倾角与冲沟倾角一致,最终确定间隔式煤柱稳定状态为:间隔式煤柱整体稳定,两侧分布凹型塑性区,间隔式采空区稳定状态为:直接顶冒落,基本顶弯曲下沉,采空区未充实,采空区中主要承载结构为间隔式煤柱。(2)分别建立平缓、冲沟地貌数值模拟模型验证得出了煤柱下应力集中传播规律,结果表明2-2#煤间隔式煤柱垂直应力最大影响深度大于层间距,即垂直应力在下组煤老顶中出现应力集中对3-1#煤层顶板运动规律存在影响,即煤柱附近顶板压力大,来压步距减小,由间隔式煤柱引起水平集中应力对下组煤开采顶板运动无影响。(3)使用FLAC数值模拟软件建立平缓、冲沟相结合模型,拟合监测点垂直应力数据得出3-1#煤层顶板载荷曲线;利用矩形弹性薄板模型边界条件多样性,分别选取四边固支、三边固支一边简支得到了冲沟及平缓地貌下3-1#煤层顶板初次来压及周期来压挠度、应力分布规律。(4)基于能量释放理论建立能量法板裂判断准则,将板内应力分布规律迭代到准则内,解释了采空区下顶板破裂演化规律。同时分析得出背、向冲沟方式及沟深为影响危险区域扩展重要因素。(5)结合实验室正交配比方案实验及南梁煤矿岩层性质铺设相似模拟模型用以研究冲沟发育地貌浅埋间隔采空区下覆岩运动特征。根据相似模拟及数值模拟计算得出3-1#煤层的所需工作阻力分别为8605KN。以南梁矿20304工作面为研究对象,对比平缓地貌与冲沟地貌的矿压显现规律得出冲沟地貌的周期来压步距、支架最大工作阻力以及来压动载系数均要大于平缓地貌,以间隔式采空区下方30107工作面为例分析间隔式煤柱下综采工作面矿压规律得出间隔式煤柱下工作面周期来压步距平均为11.43 m,其中间隔式煤柱下方周期来压步距较间隔式采空区下方小。
[Abstract]:In view of the interval mining technology of 2-2# coal seam in Nanliang Coal Mine, the study of the basic roof movement law of the coal group under the parameters of the upper and lower coal layer spacing, lithology, geomorphology and other parameters, the field investigation, laboratory experiment, theoretical calculation and numerical simulation are adopted comprehensively. By means of field measurement and analysis, the law of stress transfer under the separated coal pillar, the roof movement under the separated coal pillar and the goaf, the reasonable resistance of the support, the basic breaking mode and the law are structured. The main research results are as follows: (1) according to the geomorphological characteristics of Nanliang Coal Mine, the surface is divided into gentle geomorphology and gully geomorphology. Field observation and theoretical analysis of the normal load on the coal pillar under different geomorphological conditions, in which the slope angle of linear load on the gouge geomorphologic spaced coal pillar is the same as the dip angle of the gully. Finally, it is determined that the stable state of the spaced coal pillar is as follows: the integral stability of the spaced coal pillar, the distribution of concave plastic zone on both sides, and the stable state of the spaced goaf are as follows: the direct roof caving, the basic top bending and sinking, the goaf being unenriched, The main bearing structure in goaf is spaced coal pillar. (2) numerical simulation model of flattening and flushing geomorphology is established to verify the stress concentration propagation under coal pillar. The results show that the maximum influence depth of vertical stress is greater than the interval between layers, that is, the concentration of vertical stress in the top of the lower coal group has an effect on the roof movement of the 3-1# coal seam, that is, the roof pressure near the coal pillar is large. The pressure step distance is reduced, and the horizontal concentration stress caused by the spacer coal pillar has no effect on the roof movement of the lower coal mining. (3) using FLAC numerical simulation software, the model of flattening and gully combination is established. By fitting the vertical stress data of the monitoring points, the roof load curve of 3-1# coal seam is obtained, and the rectangular elastic thin plate model is used to obtain the boundary conditions. The first and periodic deflection and stress distribution of the roof of 3-1# coal seam under gully and flat geomorphology are obtained. (4) based on the energy release theory, the criterion of plate crack is established. The stress distribution in the plate is iterated into the criterion, and the evolution law of roof fracture in goaf is explained. At the same time, the analysis shows that the back, The method and depth of gully are important factors influencing the extension of dangerous area. (5) combined with the experiment of orthogonal proportioning scheme in laboratory and the similar simulation model of strata property in Nanliang coal mine, the characteristics of overburden rock movement in shallow buried interval gob area developed in the gully are studied. According to the similarity simulation and numerical simulation, the required working resistance of 3-1# coal seam is 8605KN, respectively. The 20304 face of south Liangshan Mine is the object of study. Comparing the regularity of rock pressure behavior between flat geomorphology and gully geomorphology, it is concluded that the interval of periodic pressure step, the maximum working resistance of the support and the coefficient of dynamic loading of the support are all larger than those of the flat geomorphology. Taking the 30107 working face below the spaced goaf as an example, the law of mine pressure of the fully mechanized coal face under the spaced coal pillar is analyzed. The average interval of the interval coal pillar under the working face is 11.43 m, in which the interval coal pillar below the interval coal pillar is less than the interval under the periodic pressure step. The spacer goaf is small below the goaf.
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TD325

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