急倾斜综采工作面底板破坏演化研究

发布时间：2018-03-13 18:25

本文选题：急倾斜煤层　切入点：底板破坏　出处：《安徽理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：急倾斜厚煤层综采工作面进行回采时,无论是开采设备、工艺还是围岩控制方面都受到技术及设备因素的约束,由于急倾斜工作面围岩具有非对称力学特征,随着工作面的推进,工作面底板也出现非对称变形破坏。这就导致底板岩层开裂、向下滑落移动,工作面底板岩层出现了大范围失稳。支架与围岩组成的支撑系统中,底板同样起到关键作用。急倾斜工作面推进过程中,底板的失稳将极大地影响支架围岩支撑系统的协调稳定性,情况恶劣会引起围岩灾变；工作面支架出现前倾,后仰等不规则翻倒现象。针对底板破坏引起的以上问题,并且为了掌握急倾斜工作面底板应力分布及破坏规律,依据急倾斜工作面的特点,分别对工作面的走向与倾向进行底板破坏机理分析,得出急倾斜底板力学极限判据解析公式,以及工作面倾向中下部、中部和中上部三个位置相应的底板最大破坏深度解析公式、工作面前方煤壁屈服宽度以及底板岩体最大破坏深度与工作面端部的水平距离。发现底板破坏与工作面长度,煤层倾角、平均容重和工作面推进距离等因素有关。通过理论分析与数值模拟可以得出,煤壁前方支承压力随着推进距离的增大而不断叠加,同样底板应力与推进距离的增大呈正比例关系。沿工作面倾向,中下部,中部与中上部三个工作面位置,底板受到垂直应力大小作用不同,中下部最小,中上部最大,中间次之,底板破坏的位移大小同样如此规律。另外工作面长度的不同,其上下两侧的侧向支承压力集中系数随着煤层倾角增大而减小,并且上测减小的速度大于下测,但是下侧支承压力集中系数始终大于上侧；另一方面,急倾斜工作面底板出现的位移是垂直位移与水平位移的拟合,说明底板塑性变形破坏且产生底鼓,在底鼓严重区域出现底板滑移,可通过降低底板应力集中、卸压的变化和此过程中应力、应变能的变化程度来控制底板因卸压而产生破坏。选用锚杆支护作为临时支护控制急倾斜煤层底板发生滑移破坏的施工工艺,可以很好的加固底板,使工作面支架在推进过程中受到底板破坏影响程度较小,通过对顶底板系统观测效果明显,可在类似条件工作面推广使用。研究成果可为急倾斜工作面底板管理提供理论依据。
[Abstract]:When fully mechanized mining face in steeply inclined thick coal seam is working, both mining equipment, technology and control of surrounding rock are restricted by technical and equipment factors, because of asymmetric mechanical characteristics of surrounding rock in steeply inclined coal face. With the advance of the working face, there is also asymmetric deformation and failure on the floor of the working face, which leads to the cracking of the floor rock layer, the downward sliding and moving, the large-scale instability of the face floor rock layer, and the support system composed of the support and the surrounding rock. The instability of the floor will greatly affect the coordination and stability of the supporting system of surrounding rock, which will cause the disaster of surrounding rock and the forward tilt of the support in the face. The phenomenon of irregular overturning, such as backward tilt, etc. In view of the above problems caused by floor failure, and in order to grasp the stress distribution and failure law of steeply inclined face, according to the characteristics of steeply inclined face, the failure mechanism of bottom plate is analyzed separately. The analytical formula of the mechanical limit criterion of steeply inclined floor and the analytical formula of the maximum failure depth of the bottom plate corresponding to the three positions in the middle, middle and upper parts of the working face are obtained. The yield width of the coal wall in front of the face and the horizontal distance between the maximum failure depth of the floor rock mass and the end of the face are found. Through theoretical analysis and numerical simulation, it can be concluded that the supporting pressure in front of coal wall is superimposed with the increase of propulsive distance. In the same way, the stress of the bottom plate is proportional to the increase of the propulsive distance. In the middle, the displacement of floor damage is the same rule. In addition, with the length of working face, the concentration coefficient of lateral support pressure on both sides of the face decreases with the increase of coal seam inclination angle, and the speed of upward measurement is larger than that of bottom measurement. On the other hand, the displacement of the floor of the steeply inclined face is the fitting of the vertical displacement and the horizontal displacement, which indicates that the bottom plate is plastic deformed and destroyed and the floor bulge is produced, but the concentration coefficient of the lower side support pressure is always greater than that of the upper side. The slippage of the bottom plate in the serious area of the bottom drum can be achieved by reducing the stress concentration, the variation of the pressure relief and the stress in the process. The change of strain energy is used to control the failure of the floor because of the pressure relief. The anchor support is used as the temporary support to control the sliding failure of the steeply inclined coal seam floor, which can be used to reinforce the floor well. The working face support is less affected by the floor damage in the process of pushing, and the observation effect of the roof and floor system is obvious, which can be popularized and used in the similar working face. The research results can provide the theoretical basis for the management of the floor in the steeply inclined working face.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD823.213;TD355

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