特厚煤层巷道顶板冒顶机理与控制技术研究

发布时间：2018-01-17 14:22

本文关键词：特厚煤层巷道顶板冒顶机理与控制技术研究　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：巷道冒顶控制问题一直以来是巷道支护领域的研究热点和难点,冒顶事故具有较高的隐蔽性、突发性和高度危险性,给人们带来了巨大的精神压力、心理恐惧和财产损失。巷道顶板的塑性破坏是产生冒顶的重要原因,揭示回采巷道冒顶机理必须掌握巷道围岩的塑性区分布规律,由于回采巷道围岩所处的应力场环境特征一般是非均匀的,这种环境下的围岩塑性破坏形态势必出现不同于均匀应力场的形态特征。因此,研究非均匀应力场条件下巷道冒顶机理,寻求解决巷道冒顶问题的实用理论和方法是煤矿开采中亟待解决的关键问题之一。采用理论分析的方法推导出不均匀应力场下围岩的塑性区分布的理论公式,并分析不均匀应力场下巷道围岩的塑性区的影响因素,得出巷道的埋藏深度、巷道的开挖半径、巷道的侧压系数以及围岩的内聚力和内摩察角等因素对巷道围岩塑性区的深度有影响,并且揭示了回采巷道冒顶机理,顶板含有软弱岩层且塑性区穿透下位坚硬岩层在该软弱岩层重新形成,伴有巨大的膨胀压力和强烈变形,这种围岩的变形破坏在现有技术条件几乎是给定的,使下位坚硬岩层受到持续、巨大的“挤压”载荷,致使其发生断裂破坏,当这种软弱岩层区域的塑性区形成产生的变形达到一定的程度后,其下位坚硬岩层则彻底失稳垮落,如果此时支护不再能承担顶板破坏岩石的重量,巷道便发生冒顶。因此,在大变形回采巷道受到不均匀应力的影响下围岩的塑性破坏及其产生的变形在现有支护条件下几乎是给定的,应懫用能够适应围岩大变形、可持续提供较高工作阻力、具有足够锚固范围的支护材料,遏制塑性区围岩的恶性扩展,保证塑性区围岩的稳定,进而消除冒顶隐患,形成了以接长锚杆为主的支护手段。本文以陈家沟煤矿8512工作面为工程实例,采用flac3D数值模拟软件,模拟了回采巷道在掘进期间、距离回采工作面10m,距离回采工作面0m等情况下,塑性破坏区分布、垂直和水平应力分布、竖直方向的位移分布、最大和最小主应力分布,巷道和工作面周边围岩体塑性区的破坏分布等云图,以了解大变形回采巷道围岩节理裂隙的发育和扩展情况,并以8512工作面为工程实例,布置观测站监测巷道在普通支护情况下和采用加长锚杆支护情况下巷道围岩的顶底板移近量和两帮移近量,确定采用加长锚杆情况下巷道的支护效果,为这类大变形回采巷道的冒顶机理和控制提出宝贵的意见。
[Abstract]:Roadway roof control problem has always been the research hotspot and difficulty in roadway support field. Roof fall accident has high concealment, sudden and high risk, which brings great mental pressure to people. Psychological fear and property loss. Plastic damage of roadway roof is an important cause of roof fall. It is necessary to master the distribution of plastic zone of roadway surrounding rock to reveal the roof falling mechanism of mining roadway. Because the surrounding rock stress field of mining roadway is generally non-uniform, the plastic failure pattern of surrounding rock in this environment is bound to be different from the uniform stress field. The mechanism of roadway roof fall under the condition of non-uniform stress field is studied. It is one of the key problems to be solved urgently in coal mining to seek practical theory and method to solve the problem of roadway roof fall. The theoretical formula for the distribution of plastic zone of surrounding rock under uneven stress field is derived by using the method of theoretical analysis. The factors influencing the plastic zone of surrounding rock of roadway under uneven stress field are analyzed and the buried depth of roadway and the excavation radius of roadway are obtained. Factors such as lateral pressure coefficient of roadway, cohesion of surrounding rock and angle of inner inspection have influence on the depth of plastic zone of surrounding rock of roadway, and reveal the mechanism of roof fall in mining roadway. The roof contains soft rock and the plastic zone penetrates through the lower hard rock layer to form again in this soft rock formation, accompanied by huge expansion pressure and strong deformation, this kind of surrounding rock deformation and failure is almost given in the existing technical conditions. So that the lower hard rock is subjected to sustained, huge "squeeze" load, resulting in fracture failure, when the formation of the plastic zone of this kind of soft rock formation to a certain extent of deformation. Its lower hard rock is completely unstable collapse, if the support can no longer bear the weight of roof damage rock, the roadway will fall. Under the influence of uneven stress in large deformation mining roadway, the plastic failure of surrounding rock and its resulting deformation are almost given under the existing supporting conditions, which can adapt to the large deformation of surrounding rock. It can provide high working resistance, enough support material with enough anchoring range, restrain the malignant expansion of surrounding rock in plastic zone, ensure the stability of surrounding rock in plastic zone, and then eliminate the hidden danger of roof fall. This paper takes 8512 face of Chenjiagou Coal Mine as an engineering example and uses flac3D numerical simulation software to simulate the excavation period of mining roadway. The distribution of plastic failure zone, vertical and horizontal stress, vertical displacement distribution, maximum and minimum principal stress distribution are obtained in the case of 10 m distance mining face and 0 m distance mining face. In order to understand the development and expansion of jointed cracks in the surrounding rock mass of large deformation mining roadway, the failure distribution of surrounding rock plastic zone around roadway and working face is discussed in this paper, and the engineering example of 8512 face is taken as an engineering example. Layout observation station to monitor the roadway in the case of ordinary support and the use of extended anchor bolt to support the surrounding rock roof and floor of the roadway near the amount and two sides to determine the roadway support effect under the condition of the use of extended bolt. Some valuable suggestions are put forward for the roof falling mechanism and control of this kind of large deformation roadway.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD327.2

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