【作者】 王红伟；

【导师】 伍永平；

【作者基本信息】 西安科技大学 ， 采矿工程， 2010， 硕士

【摘要】 大倾角煤层是指埋藏倾角为35°~55°的煤层。随着我国东部易采资源枯竭、开采重点的西移,大倾角煤层开采问题已经成为西部地区区域经济发展、东部矿区保持高产高效和可持续发展过程中亟待解决的问题。受煤层倾角、地质构造等多因素影响,大倾角煤层开采覆岩结构是一个具有复杂性、动态性、非线性的空间问题。分析大倾角煤层开采覆岩结构特征,对大倾角煤层开采理论的建立具有重大意义,对采场支护结构参数设计、采场围岩矿山压力控制、安全开采等工程实践具有重要的参考价值。本文以大倾角煤层采场大范围覆岩为研究对象,通过物理相似材料模拟、数值模拟和理论分析相结合的综合研究方法,对大倾角煤层开采覆岩运移规律、力学特征及覆岩结构进行了全面、系统研究,主要得出以下结论:1.大倾角煤层开采覆岩垮落形态沿工作面倾斜方向呈不对称拱形特征,各主要因素对顶板最大断裂高度影响程度依次为:煤层倾角>顶板岩层强度>采煤高度,并获得顶板断裂高度的预测公式: H = 168.3 ? 2.45 X 1 ? 9.53 X 2 ? 0.65X3,通过与实测数据进行了对比,验证了预测公式的合理性。2.揭示了大倾角煤层开采覆岩运移在空间上的不对称性、时间上的不同步性,得出覆岩应力非均匀分布规律,顶板应力释放区主要位于工作面中上部区域,底板应力分布表现为沿工作面倾向自上而下逐渐减小,工作面上部支承压力较小,峰值点距工作面较远,下部支承压力较大,峰值点距工作面较近。3.提出大倾角煤层开采覆岩宏观应力拱壳结构,该结构具有几何形态非对称性和应力分布不规则性,构建出应力拱壳的分析模型,得出覆岩应力拱壳形态方程,对采场围岩宏观应力拱壳和采动裂隙发育形态参数的影响因素进行系统分析,根据煤岩体的失稳破坏形式,得出应力拱壳的四种失稳模式:压缩失稳模式、拉伸失稳模式、剪切失稳模式和复合失稳模式,给出四种失稳模式的失稳判据。4.结合新疆焦煤集团有限责任公司主焦煤矿井大倾角煤层开采25112工作面具体情况,应用所构建的应力拱壳分析模型,给出该条件下应力拱壳形态方程,随着工作面的推进,该应力拱壳首先从壳顶和壳肩处发生拉伸失稳,证明分析模型是可行的。更多还原

【Abstract】 The steeply dipping seam is defined by the coal seam which pitch is between 35°~55°. As the exhaustion of kind resources in the eastern and mining focus diverts to the western, the steeply dipping seam mining has turned to be a problem that need to be solved in process of the western regional economies development and the eastern highly efficient production and sustainble development. For the multi-factor influence of coal seam pitch, geological structure and so on, overburden stucture is a complex, dynamic, nonlinear space problem in steeply dipping seam mining. Analysis of overburden structure feature in steeply dipping seam mining has great significance to the stablishment of steeply dipping seam mining theory, and has some important references on the mining support structural parameter designing, abutment controlling and safety mining and so on.The overburden migration rule, mechanics feature and structure are studied systemical and comprehensively by the integrated methods of physical simulation, numerical simulation and theory analysis in the extensive overburden of steeply dipping seam stope. The results are shown as follow:1. Overburden caving form has the asymmetrical arch characteristic along working face tendency in the steeply dipping seam mining, and influence degree of various factors to fractured zone height is in turn: the coal seam dip angle>roof rock strength>mining height, and regression formula to the roof fractured zone height in steeply dipping seam mining is obtained: H = 168.3 ? 2.45 X 1 ? 9.53 X 2 ? 0.65X3. Compared with simulation experiment data, the rationality of regression formula is verified.2. In the steeply dipping seam mining, nonsymmetry in space and asynchronism in time of overburden migration and overburden stress heterogeneous distribution rule are revealed. The roof stress release area is mainly in the upper region of working face, the floor stress reduces gradually from upper to down, abutment pressure of the upper is smaller and the distance of it’s peak value from working place is farther than those of the down.3. Surrounding rock macro stress arch-shell in the steeply dipping seam mining is proposed, which has the geometry shape asymmetry and the stress distribution heterogeneity. The analyzing model is construeted and the configuration equation is educed. Based on studying the effecting factor of surrounding rock MSAS and mining induced fracture developmental shape parameter systemically, compressive instability mode, tensile instability mode, shear instability mode and multiple instability mode of the MSAS are obtained, and instability criterion of the four kind of instability mode are given.4. Based on the condition of No.25112 working face of steeply dipping seam mining in prime coking coal mine of Xinjiang tar coal group co. ltd, the MSAS configuration equation of this condition is given by applying the analyzing mode, the tensile instability is fist happened in arch-shell roof and shoulder along with the working face advancement, and the feasibility of analyzing mode is proved.更多还原