大同矿区坚硬顶板运动特征及对综放工作面矿压影响研究

发布时间：2018-04-26 19:19

本文选题：坚硬顶板 + 覆岩“拱壳”大结构　；参考：《辽宁工程技术大学》2015年博士论文

【摘要】：大同矿区赋存有侏罗系和石炭系“双系”煤层。开采石炭系特厚煤层的同忻矿,在覆岩多层坚硬顶板和上覆侏罗系多煤层开采残留煤柱等复杂的开采条件下,开采期间矿压显现强烈。因此,对大同矿区坚硬顶板运动特征及综放工作面矿压影响进行研究,为大同矿区特厚煤层安全高效开采提供理论指导。论文建立“拱壳”覆岩大结构力学模型,对覆岩大结构的几何特征和运动特征进行分析,坚硬岩层的强度、厚度和采厚共同决定了大结构的尺度,各关键层控制着空间覆岩大结构的形成和演化；结合关键层理论和材料力学的相关理论,确定了工作面覆岩大结构初次失稳和周期失稳的能量计算公式,计算结果表明大结构形成和失稳对矿压显现具有重要的控制影响,揭示了大结构形成过程的围岩应力升高、结构失稳时能量突然释放和失稳后围岩应力降低的矿压显现特征。基于改进的果蝇优化算法和支持向量机理论,建立MFOA-SVM覆岩破坏高度预计模型,对石炭系特厚煤层工作面开采覆岩破坏高度进行预测,预测结果与EH4物理探测结果相互吻合,模型具有较好的适用性；采用相似材料模拟方法,分析双系煤层开采的上覆岩层移动、破坏垮落特征以及相互之间的开采影响,坚硬岩层的破断控制工作面矿压显现强度；运用FLAC3D数值模拟软件,研究了侏罗系煤层群和石炭系煤层开采围岩破坏特征,双系煤层开采后采空区裂隙相互联通；采用微震监测分析了双系煤层开采影响下的微震事件时空分布特征、微震事件的能量和频次特征,得到工作面后方300 m-500 m范围的采空区覆岩仍然在运动,工作面在侏罗系重叠煤柱下方区域开采覆岩运动更为强烈。采用UDEC数值模拟软件,分析侏罗系煤柱影响下的石炭系工作面采动应力演化规律,工作面回采至侏罗系煤柱对应区域工作面围岩应力升高,较非煤柱区域提高了32%-37%；通过对回采巷道和工作面进行矿压监测,确定回采巷道和工作面的矿压显现的时空演化规律,进一步验证了大结构对矿压显现具有一定的控制作用；对不同工作面推进速度的围岩应力、支架工作阻力和覆岩运动特征进行分析,确定特厚煤层工作面推进速度对矿压显现的影响,综放工作面推进速度越快工作面矿压显现越明显。对同忻矿强矿压显现的能量特征进行分析,确定同忻矿的强矿压显现是覆岩大结构失稳、临近采空区侧向支承压力、本工作面超前支承压力和侏罗系煤柱应力传递多因素空间耦合作用引起的。
[Abstract]:There are Jurassic and Carboniferous "double system" coal seams in Datong mining area. In Tongxin Coal Mine of Carboniferous extra thick seam, under the complicated mining conditions such as overburden multi-layer hard roof and overlying Jurassic multi-seam mining residual coal pillar, the mine pressure appears strongly during mining. Therefore, the characteristics of hard roof movement in Datong mining area and the influence of mine pressure on fully mechanized caving face are studied to provide theoretical guidance for safe and efficient mining of extra thick coal seam in Datong mining area. In this paper, the mechanical model of "arch shell" overburden rock structure is established, and the geometric and kinematic characteristics of overburden rock structure are analyzed. The strength, thickness and mining thickness of hard rock layer together determine the scale of large structure. Each key layer controls the formation and evolution of the large structure of overlying rock in space, combined with the theory of critical layer and the theory of mechanics of materials, the energy calculation formulas for the first and periodic instability of large overburden structure in working face are determined. The calculation results show that the formation and instability of large structures have an important control effect on the formation of rock pressure, and reveal the characteristics of rock pressure behavior in the process of formation of large structures, such as the increase of surrounding rock stress, the sudden release of energy during structural instability and the decrease of surrounding rock stress after instability. Based on the improved Drosophila optimization algorithm and the support vector machine theory, the prediction model of MFOA-SVM overburden failure height is established, and the mining overburden failure height of the Carboniferous coal face is predicted. The predicted results are consistent with the EH4 physical detection results. The model has good applicability, the similar material simulation method is used to analyze the overlying strata movement, the characteristics of failure and caving and the influence of mining on each other in the mining of double system coal seam, and the breaking of hard rock strata controls the strength of rock pressure behavior in working face. The failure characteristics of surrounding rock of Jurassic coal seam group and Carboniferous coal seam mining are studied by using FLAC3D numerical simulation software. Microseismic monitoring is used to analyze the space-time distribution characteristics of microseismic events, the energy and frequency characteristics of microseismic events under the influence of double-system coal seam mining, and the results show that the overburden is still moving in the gob area of 300m-500m behind the working face. The mining overburden movement is stronger in the area below the superimposed pillar of Jurassic system. By using UDEC numerical simulation software, the evolution law of mining stress in Carboniferous coal face under the influence of Jurassic pillar is analyzed, and the surrounding rock stress of coal face in the corresponding area of coal pillar of Jurassic system is increased. Compared with the non-pillar area, it has been improved by 32-37.The time and space evolution law of the mining roadway and the coal face is determined by monitoring the mine pressure of the roadway and working face, which further verifies that the large structure has certain control function to the rock pressure appearance. Based on the analysis of surrounding rock stress, support working resistance and overburden movement characteristics of different working faces, the influence of advancing speed on the rock pressure in the face of extra thick coal seam is determined. The faster the advance speed of fully mechanized caving face, the more obvious the mine pressure appears. Based on the analysis of the energy characteristics of strong rock pressure in Tongxin mine, it is determined that the strong rock pressure behavior of Tongxin mine is the instability of overburden structure and the lateral bearing pressure near goaf. The multi-factor spatial coupling between the leading supporting pressure and the stress transfer of the Jurassic coal pillar in this working face is caused.
【学位授予单位】：辽宁工程技术大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TD323

【相似文献】