王家山矿急倾斜煤层长壁开采覆岩破断机理及强矿压控制方法

发布时间：2018-07-04 21:50

本文选题：急倾斜煤层 + 覆岩断裂机理　；参考：《北京科技大学》2015年博士论文

【摘要】：急倾斜特厚煤层长壁综放开采过程中由于采空区充填不均匀,直接顶冒落后基本顶断裂呈现非对称特征,造成了覆岩变形、破坏、能量分布、应力传递等均具有非对称特征。因此,需要对急倾斜煤层覆岩断裂机理与强矿压控制方法进行深入研究,对丰富该类煤层矿压控制理论和指导现场实践均有重要意义。本研究以王家山煤矿工程地质条件与强矿压显现特征为背景,利用室内实验、理论分析、数值实验和现场观测等综合研究手段,研究了急倾斜煤层开采覆岩初次、周期顶板破断机理,揭示了煤、岩非对称应力分布特征与演化规律,提出了强矿压显现危险区域预测与定向弹性能释放强矿压控制方法。论文取得的主要研究成果有： (1)基于弹性力学理论,建立了横纵荷载作用下急倾斜煤层基本顶的薄板力学模型,分析了基本顶上、下板面的应力分布特征,获得了基本顶断裂线发育轨迹与破坏区演化规律,提出了急倾斜煤层基本顶的初次破断“V—Y”型断裂模式。研究表明,急倾斜煤层基本顶初次断裂的空间顺序为“中上部→中下部→上部→下部”。结合数值模拟、现场监测等手段,验证了基本顶初次断裂过程中采场围岩应力场分布及矿压显现具有时序性和非对称特征； (2)基于弹性力学理论,建立了急倾斜综放面推进过程中基本顶由小三角形悬板→大三角形悬板→斜梯形板转化的薄板力学模型,计算出三种形状基本顶的上、下板面的应力分布,揭示了断裂线发育轨迹与破坏区演化过程,阐明了急倾斜煤层基本顶周期破断的“四边形”型断裂模式。研究表明,急倾斜煤层基本顶周期断裂的空间顺序为“中下部→中上部→上部→下部”。结合数值模拟、现场监测等手段,验证了基本顶周期断裂过程中采场围岩应力场分布及矿压显现具有时序性和非对称特征； (3)采用离散元数值模拟及现场实测等手段,揭示了王家山矿急倾斜特厚煤层(群)回采煤、岩应力分布特征与演化规律。发现了急倾斜综放工作面煤体支承压力动压区呈“圆弧形”分布,稳压区呈“矩形”分布的非对称分布特征。利用离散元数值模型证明了区段工作面顶板周期断裂同样符合“四边形”周期断裂模式； (4)以王家山煤矿工程地质条件与强矿压显现特征为背景,采用综合指数法、超静定梁理论、统计学理论等方法,提出了“井田→工作面→近场→定点”层次化危险区预测与关键部位监测方法,并针对不同危险等级制定了相应的强矿压防治方案; (5)采用数值模拟、现场实测等手段,研究了王家山矿急倾斜煤层开采强矿压致灾机理,即上部基本顶在侧支承压力与顶板断裂的综合影响下,可能发生混合型强矿压。中部基本顶断裂可能发生诱发型强矿压,下部基本顶较稳定易发生能量聚集型强矿压； (6)发现了超前顶板重点卸压区域的弹性能释放后由能量转移与积聚而形成“人”字型能量分叉形态,构成了顶板防冲卸压后的主要来压路径。据此提出了急倾斜特厚煤层弹性能定向释放强矿压控制方法,将方法分为悬顶能量释放与次生能量消耗两个阶段,并分析了各阶段的作用。通过顶板动态监测与地音监测检验,证明此方法能够在有效的缩短悬顶面积,减小工作面顶板压力与来压步距的同时,降低由顶板卸压造成次生灾害的可能。
[Abstract]:In the process of long wall fully mechanized coal caving in steep and extra thick coal seam, due to the uneven filling in the goaf, the direct top and backward basic roof fracture presents asymmetrical characteristics, which causes the deformation, damage, energy distribution and stress transfer of overlying rock. Therefore, the mechanism of overlying coal seam fracture and the control method of strong ore pressure need to be deep. The study is of great significance for enriching the theory of coal seam pressure control and guiding the field practice.
In this study, with the background of the engineering geological conditions of Wangjiashan coal mine and the characteristics of strong ore pressure, and using the comprehensive research means such as laboratory experiment, theoretical analysis, numerical experiment and field observation, the mechanism of the initial overburden and periodic roof breaking in the mining of steep coal seam is studied, and the characteristics and evolution law of the asymmetric stress distribution of coal and rock are revealed, and the strength of the coal and rock is revealed. Prediction of dangerous area of rock burst and directional elastic energy release method for strong ground pressure control.
The main research results obtained in this paper are as follows:
(1) based on the theory of elastic mechanics, a sheet mechanical model of the basic roof of a steep inclined seam under the action of transverse and longitudinal loads is established. The stress distribution characteristics of the basic top and lower plate surface are analyzed, the development track of the basic top fracture line and the evolution law of the failure area are obtained, and the first break "V Y" type fracture mode of the basic top of the steep seam is put forward. It is shown that the spatial order of the initial breakage of the basic top of the steep seam is "middle and upper middle lower to the upper part". Combined with numerical simulation and field monitoring, the distribution of stress field of surrounding rock in the stope and the characteristics of time series and asymmetric are verified.
(2) based on the theory of elastic mechanics, the mechanical model of thin plate which is basically converted from small triangular suspension to large triangular suspension to oblique trapezoidal plate in the process of rapid inclined fully mechanized caving is established, and the stress distribution of the upper and lower surface of the three kinds of basic top is calculated, the evolution process of the fracture line and the damage zone is revealed, and the steep slope is clarified. The study shows that the spatial order of the basic top periodic fracture of the steep coal seam is "middle and lower middle upper, upper to the lower". Combining numerical simulation and field monitoring, the distribution of stress field of surrounding rock in the stope and the rock pressure display tool in the basic top period fracture process have been verified. Sometimes the character of order and asymmetry;
(3) by means of discrete element numerical simulation and field measurement, the distribution characteristics and evolution laws of the steep inclined extra thick coal seam (Group) coal seam (Group) in Wangjiashan mine are revealed. The distribution of "circular arc" in the dynamic pressure area of the bearing pressure in the coal body of the steep inclined fully mechanized caving face is found, and the asymmetric distribution characteristic of the "rectangular" distribution in the stable pressure zone is found. The numerical model shows that the periodic fracture of the roof is also consistent with the "quadrilateral" periodic fracture mode.
(4) taking the engineering geological conditions of Wangjiashan coal mine and the characteristics of strong ore pressure as the background, using the comprehensive index method, the statically indeterminate beam theory and the statistical theory, the paper puts forward the method of the dangerous zone prediction and the key position monitoring in the "well field, the working face, the near field and the fixed-point", and formulating the corresponding strong ore pressure and prevention against the different dangerous grades. Treatment plan;
(5) by means of numerical simulation and field measurement, the mechanism of strong ore pressure caused by steep inclined coal seam mining in Wangjiashan mine is studied, that is, under the comprehensive influence of the lateral support pressure and roof fracture in the upper basic top, it may occur mixed type of strong ore pressure. The middle basic top fault may induce strong ore pressure, and the lower basic roof is stable and easy to occur. Mass accumulation type strong ore pressure;
(6) it is found that the energy transfer and accumulation of the key pressure relief area of the top roof are released from the energy transfer and accumulation to form the "human" type energy bifurcation form and form the main pressure path of the roof after the pressure relief and pressure relief. According to this, the method of controlling the elastic energy directional release and strong pressure control of the steep and extra thick coal seam is put forward, and the method is divided into the release of the suspended roof energy and the energy release method. The secondary energy consumption is two stages, and the function of each stage is analyzed. Through the dynamic monitoring of roof and ground sound monitoring, it is proved that this method can effectively shorten the area of the suspended top, reduce the roof pressure and the step distance of the working face, and reduce the possibility of the secondary disaster caused by the roof pressure unloading.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TD323;TD823.213

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