【作者】 李磊；

【导师】 柏建彪；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2013， 博士

【摘要】 随着巷道断面的增大，托顶煤巷道支护难度逐渐增大，尤其在弱面的影响下，支护问题更为突出，采用现有的支护理论与技术，难以满足大断面托顶煤巷道支护要求。本文综合运用理论分析、数值计算、现场试验等方法，对大断面托顶煤巷道围岩灾变机制与控制技术进行了系统研究，主要研究成果为：（1）采用复变函数理论，给出矩形巷道围岩应力的解析解，分别研究得到低围压和高围压下不同宽高比、埋深以及侧压系数对矩形巷道围岩应力分布的影响规律。（2）采用数值计算的方法，分析了巷道宽度对弱面应力分布、位移分布以及围岩变形与破坏的影响规律，并对大断面巷道和小断面巷道的顶板变形破坏特征进行对比分析，揭示了大断面托顶煤巷道的灾变机制：随着巷道宽度的增大，围岩沿弱面的水平位移也在不断增大，弱面附近的围岩剪切破坏更加严重，容易发生离层，顶板下沉量不断增大且下沉速度也在增加，顶板浅部围岩的破坏方式由剪切破坏或拉剪混合破坏向以拉破坏为主过渡，拉破坏宽度和范围持续增加，其稳定性急剧下降，当顶板离层和变形而形成的张拉应力大于托顶煤巷道顶板抗拉强度时，托顶煤巷道发生离层、冒顶等灾变现象。（3）建立托顶煤巷道顶板两端弹性嵌简支承梁力学模型，通过对极限平衡区内煤帮与顶板接触面的应力分析，综合考虑围岩的损伤，给出弹性嵌简支端的位置和极限平衡区内接触面正应力分布式，基于托顶煤巷道大断面的判别依据，通过对托顶煤巷道大断面宽度的力学解析，给出托顶煤巷道顶板稳定与巷道宽度等因素的关系式，以王庄煤矿7105工作面运输巷为例，求出该条件下托顶煤巷道大断面宽度为4.7m，研究认为当巷道的宽度大于等于4.7m时，托顶煤巷道顶板中部拉破坏深度超过锚固区的厚度，巷道维护困难，7105工作面运输巷宽度大于4.7m时称为大断面巷道。（4）提出大断面托顶煤巷道顶板的“三区”分布，分别为弱面剪切位移峰值区、弱面离层区和拉破坏极不稳定区，为围岩控制的关键部位，针对“三区”的变形破坏特征，开发了弱面剪切位移峰值区斜拉锚索支护、拉破坏极不稳定区小间距高预应力锚杆支护以及弱面离层区层次锚杆支护的顶板“三区”关键部位加强支护技术。依据大断面托顶煤巷道围岩技术，针对王庄煤矿大断面托顶煤巷道埋深为400m、巷道宽度为5.5m的生产地质条件，在王庄煤矿7105工作面运输巷进行了工业性试验，现场应用表明，“顶板三区关键部位加强支护、层次锚杆支护”的围岩控制技术有效控制了围岩变形，实现了围岩及支护结构稳定。更多还原

【Abstract】 With the increase of roadway section, support of gateroads for fully mechanizedcaving faces become difficult increasingly. The problem of supporting is prettyserious especially under the impact of plane of weakness. It is difficult to meet theneed from supporting of large-section gateroads for fully mechanized caving faces byutilizing existing theories and techniques of supporting. Based on the analysis of lawof distribution for deep tectonic stress in Juye coalfield, the thesis performs asystematical research on the mechanism of failure and control techniques forlarge-section gateroads for fully mechanized caving faces by using theoreticalanalysis, numerical calculation, field test and other means synthetically. The mainfindings are:（1）Analytic solutions for stress field of rectangular roadway are got by usingcomplex variable. The effect on stress field of rectangular roadway from aspect ratio,buried depth and coefficient of horizontal pressure under confining pressure of highlevel and low level are investigated. Based on these laws, criterion for large section isput forward.（2）Mechanism of interaction between width of roadway and plane of weaknessas well as law of influence on modes of roof failure from width of roadway areanalyzed through numerical calculation. Mechanism of roof failure for large-sectiongateroads for fully mechanized caving faces is revealed. With the growth of width ofroadway, horizontal displacement in surrounding rocks also increases constantly.Shear failure in surrounding rocks around plane of weakness become increasinglyserious, which would contribute to bed separation. Roof subsidence increasescontinuously, as well as subsidence speed. Modes of failure in fallow surroundingrocks transform from shear failure or combination of tensile and shear failure totensile failure. The width and scope of tensile failure goes up gradually with itsstability decreasing dramatically. Bed separation and deformation would occur whenthe tensile stress resulting from bed separation and deformation outnumbers tensilestrength of roof.（3）Mechanical model of supporting beam with elastic build-in on both sides isestablished. The position of build-on and distribution of normal stress on contactsurface are achieved with the consideration of the effect of damage. Relationshipbetween stability of roadway roof and width of roadway is got on the basis of criterion for large section. These theories are applied in headentry of7105working face inWangzhuang coal mine. The width of section-large gateroads for fully mechanizedcaving faces is determined to4.728m. When the width of roadway exceeds4.728m,depth of tensile failure outnumbers the thickness of anchorage zone. In this case, it isdifficult to maintain the roadway which can be defined as large-section roadway.（4）Position of the plane of weakness determines the stress state of the roof oflarge-section gateroads for fully mechanized caving faces. When plane of weaknessexists in the sides of the roof, right above the roof or the middle and fallow part ofroof, the roof of large-section gateroads for fully mechanized caving faces locates inhigh-level shear displacement zone, shear slump bed separation zone and tensiledamage zone respectively. In allusion to the mechanism of the three modes of failure,surrounding rocks control techniques named “intensive and hierarchical anchorsupporting for critical parts of three zones” is put forward.（5）In allusion to large-section gateroads whose width and buried depth are5.5m and400m respectively for fully mechanized caving face in Wangzhuang coalmine, field test was performed in headentry and open-off cut for7105working faceby using surrounding rocks control techniques for large-section gateroads. Field testsuggested that surrounding rocks control techniques named “intensive andhierarchical anchor supporting for critical parts of three zones” controlled thedeformation of surrounding rocks effectively and achieved the stability of surroundingrocks and supporting structure.更多还原