【作者】 朱庆华；

【导师】 缪协兴；

【作者基本信息】 中国矿业大学 ， 工程力学， 2010， 博士

【摘要】 随着煤矿开采深度的不断增加,巷道围岩的稳定性日趋恶化,对支护技术的要求越来越高,给煤矿高效安全集约化生产带来严重影响。跨采动压巷道围岩的稳定性一直是煤矿安全生产的难题,特别对于深部骑跨采动压巷道围岩需经历煤层工作面开采引起的支撑压力影响长期作用,围岩变形表现出强烈的流变特征,给巷道围岩的稳定性控制带来困难。本文综合运用理论分析、数值模拟和现场观测等方法对深部骑跨采动压巷道围岩稳定性的力学机理及控制方法等进行了系统研究,取得了如下主要研究成果:(1)建立了骑跨采动压巷道围岩流变特征分析的力学模型,应用粘弹塑性理论分析了巷道围岩应力分布特征及对围岩稳定性的影响,得到了巷道围岩应力与变形随巷道埋深H、巷道距上部煤层工作面端头的垂直距离、水平距离的变化规律,给出了巷道的应力及变形随时间变化的估算表达式。(2)借助于数值模拟方法,分析了骑跨采动压巷道在煤层工作面回采时的稳定性特征,得到了巷道围岩应力、变形及塑性区范围等随巷道埋深、巷道与上部煤层工作面端头垂直距离、水平距离的变化规律。研究表明:当煤层工作面端头距巷道的水平距离较小时,巷道围岩的稳定性需经受工作面前方和工作面端头侧向支撑压力的影响;巷道的顶板与外帮受上方煤层工作面影响最为强烈;巷道顶板及外帮长的时间高应力作用引起的流变效应是给形成巷道围岩稳定性严重隐患的重要原因。(3)分析了骑跨采动压巷道围岩的流变特性,考察了巷道围岩应力、变形和塑性破坏区的时间相关性特征,得到了巷道与煤层工作面端头的垂直间距、水平间距、巷道埋深等对巷道围岩流变及破坏特征的影响规律,结果表明:围岩的应力随时间呈降低趋势,应力集中区逐渐向围岩深部扩大;围岩变形、塑性区范围随时间有较大幅度增加,并表现为初期增加较快,约60天后围岩变形基本趋于稳定;围岩流变主要由粘塑性蠕变导致。(4)针对某矿区骑跨采动压巷道的稳定性特点,设计了相应的现场观测研究方案,对巷道的表面位移、围岩内部变形位移、锚杆(索)锚固状态等方面分别进行了长期的监测研究,得到了上方煤层工作面采动及采动后相当长一段时间内巷道的变形破坏规律及流变特征。(5)利用注浆加固提高围岩的基本力学特性及抗流变性能的特点,结合锚杆(索)支护技术,针对性地提出了骑跨采动压巷道稳定性控制的锚注联合支护方案,设计了适合于试验巷道条件的专用注浆锚杆。经现场实测证实,可有效地控制骑跨采动压巷道流变变形,确保上方工作面回采期间巷道的稳定与安全。研究成果可为类似条件下巷道围岩稳定性控制提供重要参考。更多还原

【Abstract】 With the increasing depth of coal mining, the stability of roadway surrounding rock is deteriorating, and the requirements on support technology are increased, which has serious impact on the efficient and safe intensive production in coal mine. The surrounding rock stability of roadway affected by cross mining(RCM)has always been a difficult problem of safe production in coal mine. Especially for the roadway affected by deep riding mining(RADRM), which means that the roadway located at the bellow of the working face and the advancing direction of working face is along with the roadway axis,its surrounding rock is affected by the support pressure caused from the coal face mining for a long time and the deformation shows strong rheological properties, which gives rise to difficulties in stability control of surrounding rock. A synthetically study means combined with theoretical analysis, numerical simulation and field observations is applied to study systematically the mechanical mechanism of the stability of RADRM in deep and its control ways. And the study results with innovative significance are shown in the following:(1) The mechanics model of RADRM is established to analyze the rheological properties of surrounding rocks, and the visco-elastic-plastic theory is applied to study the stress distribution of roadway surrounding rock and its influence on the stability of surrounding rock and obtain the distribution law of the stress and deformation of roadway surrounding rock with the changing of the roadway depth H, the vertical distance h and the horizontal distance b between the roadway and the end of the working face above, and the estimated expression of the stress and the deformation of roadway with the time changing are respectively gained.(2) With the help of numerical simulation, the stability characteristics of RADRM in coal seam mining are analyzed and obtain the distribution law of the stress, the deformation and the plastic zone size of roadway surrounding rock with the changing of the roadway depth H, the vertical distance h and the horizontal distance b between the roadway and the head of the working face above. The study results indicate that when the horizontal distance b between the roadway and the head of the working face above is smaller, the roadway stability is affected by the advanced abutment pressure in working face and the lateral abutment pressure. Especially the roadway roof and the roadway side near to the end of working face are affected seriously by the coal seam mining above, and their rheological effect deduced from the high stress effect for a long time is the important reason for the hidden trouble of the roadway stability.(3) The rheological properties of the surrounding rock of RADRM is analyzed to investigate the time dependent properties of the stress, the deformation and the plastic failure zone of roadway surrounding rock, and obtained the influence of the roadway depth H, the vertical distance h and the horizontal distance b between the roadway and the end of the working face above on the rheological and failure properties of the roadway surrounding rock. The study results indicate that the stress of surrounding rock tended to decrease with time passing, and the stress concentration zone gradually expanded to the deep surrounding rock; the deformation and the plastic failure zone of surrounding rock are increase sharply with time passing, showed rapid initial increase and the surrounding rock deformation tends to stability after 60 days. The rheology of surrounding rock is mainly resulted from its viscoplastic creep.(4) Aimed at the stability of RADRM in a coal mine, the corresponding field observation scheme is designed. We have conducted long-term monitoring on the surface displacement of roadway, the deformation of surrounding rock inside, the anchorage situation of bolt(cable), and obtained the deformation failure law and rheological properties of the roadway during the coal seam mining and for a long time after mining.(5) Grouting can improve the basic mechanical properties and Anti-rheological properties of surrounding rock. Taking advantage of this characteristic and combined the bolt(cable) support technology, the combined bolt-grouting support scheme is presented to control the stability of RADRM, and designed the special grouting anchor adapted to the testing roadway conditions. Field observation were carried out to validate that this support technology can control effectively the rheology deformation of RADRM and insure the stability and safe of the roadway surrounding rock during the coal seam mining above.The study results can provide important reference to stability control of the roadway surrounding rock on the similar condition.更多还原