断层影响区域采动诱冲机制及防治技术研究

发布时间：2018-03-25 13:27

本文选题：冲击地压　切入点：断层失稳　出处：《山东科技大学》2017年硕士论文

【摘要】：随着矿井开采深度的逐渐增加,工作面回采和巷道掘进过程中揭露的断层构造显著增加,然而这些断层构造往往处于非稳定平衡状态,开采极易使得断层活化,从而诱发冲击。因此,本论文采用理论分析、数值模拟及现场监测方法,研究了断层控制区受采动影响诱发冲击危险机制及其防治技术。取得如下主要研究成果:(1)基于库仑-摩尔定律,分析了断层单元体应力状态及断层面正、切应力状态,并运用算理分析法,获得了断层面正、切应力与断层倾角及单元体应力之间的变化规律。结果表明:岩体内最小主应力越大,则最大主应力变化曲线向上的“开口”越小,则岩体发生破坏的可能性越大;断层面正应力与切应力均随断层面倾角的增加而呈类双曲线趋势降低,且降低程度不断增加。(2)运用剪切失稳理论,对比分析了断层面切应力与正应力之间的比值与断层内摩擦角正切值大小,探讨了断层冲击失稳特性;同时运用尖点突变理论,估算了断层冲击失稳时能量释放量及震级。结果表明:断层冲击地压能量释放量随比值n及岩体均质度m变化,呈类双曲线形趋势变化,且随着比值n的增大而逐渐减小;当岩体均质度m—定时,断层冲击地压能量释放量随着比值n的减小而逐渐增加,即断层带宽度越大,断层冲击失稳释放的能量则越小。(3)利用FLAC数值软件,模拟分析了正逆断层、断层倾角及断层落差变化下煤壁前方及煤层与断层交界处的垂直应力和弹性应变能密度的演化规律,并探讨了其对断层稳定性的影响。结果表明:在同一煤岩体参数及工作面布置条件下,断层落差变化对煤体垂直应力及弹性应变能的影响最大,断层倾角变化次之,正逆断层的影响最小,而且在断层控制区域采动诱发的冲击危险性逐渐降低。(4)依据工作面地质条件和开采技术条件,运用综合指数法和可能性指数诊断法评价了工作面开采范围内的冲击危险性和分析了其诱发因素;同时模拟研究了钻孔间距和钻孔直径变化对钻孔卸压效果的影响。结果表明:对于一定的地质条件而言,钻孔间距越小,钻孔直径越大,则钻孔卸压效果越明显;钻孔卸压后,钻孔围岩应力钻孔两端部分较中部钻孔围岩应力小,呈单峰变化。
[Abstract]:With the gradual increase of mining depth, the fault structures exposed in the mining face and roadway excavation process increase significantly. However, these fault structures are often in an unstable equilibrium state, mining is easy to make the fault activation, Therefore, theoretical analysis, numerical simulation and field monitoring methods are used in this paper. In this paper, the mechanism of impact hazard induced by mining in fault control area and its prevention techniques are studied. The main research results are as follows: 1) based on Cullen Moore's law, the stress state of fault unit and the normal and shear stress state of fault plane are analyzed. The variation law of normal shear stress, fault dip angle and element stress in fracture plane is obtained by using the method of calculation. The results show that the larger the minimum principal stress in rock, the smaller the "opening" of the upward curve of maximum principal stress. The higher the possibility of rock mass failure is, the more the normal stress and shear stress of fault plane decrease with the increase of dip angle of fault plane, and the degree of decrease is increasing. 2) the theory of shear instability is used. The ratio of shear stress to normal stress in fracture plane and the tangent value of internal friction angle of fault are compared and analyzed, and the characteristics of fault impact instability are discussed, and the cusp catastrophe theory is used. The energy release and magnitude are estimated during the impact instability of the fault. The results show that the energy release of the fault impact ground pressure varies with the ratio n and the rock mass homogeneity m, and changes in a hyperbolic trend, and decreases gradually with the increase of the ratio n. When the rock mass homogeneity is m-timing, the energy release of the rock burst increases with the decrease of the ratio n, that is, the larger the width of the fault zone, the smaller the energy released by the impact instability.) using the FLAC numerical software, the positive reverse fault is simulated and analyzed. The evolution law of vertical stress and elastic strain energy density in front of coal wall and at the junction of coal seam and fault under the change of fault dip angle and fault drop. The results show that the variation of fault drop has the greatest influence on vertical stress and elastic strain energy of coal body under the same coal and rock mass parameters and working face arrangement, and the change of fault dip angle is the second. The impact of the reverse fault is the least, and the impact risk induced by mining in the fault control area is gradually reduced. (4) according to the geological conditions of the face and the technical conditions of the mining, The comprehensive index method and possibility index diagnosis method are used to evaluate the impact risk in the mining area of the working face and to analyze its inducing factors. At the same time, the influence of the variation of borehole spacing and diameter on the borehole pressure relief effect is studied. The results show that the smaller the borehole spacing, the larger the borehole diameter, the more obvious the borehole relief effect is. The stress of the borehole surrounding rock is smaller than that of the central borehole, showing a single peak variation.
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD324

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