大倾角大采高长壁综采工作面煤壁稳定性研究与应用.pdf

万方数据 Research on the Stability of Coal Wall on Large Mining Height Longwall Face in Steeply Inclined Coal Seams and Its Application Dissertation ted to Xi’an University of Science and Technology In Partial Fulfillment of the Requirement For the Degree of Doctor of Engineering By Liu Kongzhi College of Energy Engineering Dissertation Directed By Professor Wu Yongping Dec, 2017 万方数据 万方数据 万方数据 要还受工作面煤层倾角、采高变化、支架工况、周期来压、回采工艺、仰伪斜角、工作 面推进速度和采场顶板坚硬程度等因素的影响。通常条件下，工作面煤层倾角、采高、 仰伪斜角越大， 推进速度越小， 工作面煤壁发生片帮的可能性、 影响范围和强度就越大， 煤壁片帮发生频次也越高。 煤壁支承压力的非对称性导致煤壁变形和内力的非对称性，工作面中上部区域（约 0.66 工作面斜长处）煤壁（岩梁）变形最大；煤层倾角增大煤壁变形和内力减小；工作 面长度增加，煤壁变形增大、内力减小。煤壁铅直方向上变形和内力分布呈现非对称特 征， 其变形量最大区域在煤壁的中上部区域 （0.6 倍采高） ， 该区域煤壁所受拉应力较大， 是煤壁失稳的高发区域。 基于新疆焦煤集团 2130 煤矿 25221 大倾角大采高工作面煤壁片帮控制工程实践， 成功实施了“严控工作面“R-W-S-F”系统稳定、坚硬顶板超前松动预爆破弱化、工作 面煤壁超前预加固、小仰伪斜角度工作面布置、全时动态工作面矿压监测”的煤壁片帮 综合防控技术，有效地解决了大倾角大采高条件下工作面煤层片帮、顶板漏冒问题，保 障了工作面安全高效生产，社会与技术经济效益良好。 关 键 词大倾角煤层；大采高；煤壁片帮； “R-W-S-F”系统；稳定性控制； 研究类型应用基础研究 万方数据 万方数据 The surrounding rock stress is redistributed in longwall working face with large mining height in steeply inclined thick seam, stress released area ed in roof and floor, stress concentrated area ed in T-junction. Affected by dip angle of coal seam, distribution of surrounding rock stress presents asymmetrical characteristics along inclination, with vertical stress of rib in lower area of working face larger than that in upper and middle areas. The displacement of coal wall increased linearly from up to down along inclination, with vertical displacement larger than horizontal displacement. The stability of coal wall is affected significantly by mining height and dip angles of coal seam. With increasing thickness of coal seam mining, vertical stress of coal wall transferred to front continuously, the maximum abutment pressure and its distance coal wall increased. Horizontal displacement of coal wall reduced and vertical displacement increased, leading to probability increase of coal splling. With increasing dip angle of coal seam, the value and influence area of concentrated stress in coal wall decreased gradually with small variety range, and coal wall was easy to slipping down and a large-scale coal wall spalling ed. The coal wall spalling happened with high frequency, large range, sub-regional, spread and slip characteristics in longeall face with large mining height in steeply inclined seam. Stability of coal wall is not only influenced by coal strength, gas exceeding the limit and gas extraction, but also mainly by dip angle of coal seam, variety of mining height, working characteristics of support, periodic weighting, extraction technology, oblique angle, advancing speed of working face, hardness of roof and so on. With the increasing of dip angle of coal seam, mining height and oblique angle of working face and the decreasing of advancing speed, the possibility and frequency, influence range and degree of coal wall spalling increased. The asymmetry of abutment pressure leads to asymmetry of deation and internal force in coal wall. The deation of the coal wall is the largest at about 0.66 times length of working face in upper area. With increasing dip angle of coal seam, the deation and internal force decreased in coal wall. With increasing lenght of working face along inclination, the deation increased and internal force decreased in coal wall. Asymmetric characteristics of deation and internal force in vertical direction of coal wall was revealed. The maximum deation appeared at 0.6 times mining height of coal wall in upper and middle area, where the tensile stress was large and was the location of frequent instability of coal wall. Based on the controlling practice of coal wall spalling of No. 25221 working face with large mining height in steeply inclined seam in the 2130 Coal Mine of Xinjiang Coking Coal 万方数据 Group, the comprehensive preventing and controlling technology of coal wall spalling was proposed, with controlling stability of R-W-S-F system, pre-blasting weaken of hard roof, advance strengthening of coal wall, layout of false-inclined working face with oblique angle, full-time mine pressure monitoring. The coal wall spalling and roof caving in front of support were solved effectively, safety and efficiency production of working face was achieved, beneficial technical and economic application was realized. Key words Steeply inclined seam; Large mining height; Coal wall spalling; R-W-S-F system; Stability control Thesis Applied basic research 万方数据 目 录 I 目 录 1 绪 论 ....................................................................................................................................... 1 1.1 选题背景及研究意义 ...................................................................................................... 1 1.2 国内外研究现状 .............................................................................................................. 1 1.2.1 大倾角煤层长壁开采历史沿革与现状 .................................................................... 1 1.2.2 大采高综采及煤壁稳定性研究历史沿革与现状 .................................................... 5 1.2.3 国内外研究综述 ...................................................................................................... 10 1.3 研究内容 ........................................................................................................................ 10 1.4 研究方法和技术路线 .................................................................................................... 11 2 大倾角大采高工作面煤壁稳定性特征现场观测 .............................................................. 13 2.1 工作面概况 .................................................................................................................... 13 2.1.1 工作面地质条件 ...................................................................................................... 13 2.1.2 采煤方法及回采工艺 .............................................................................................. 14 2.2 工作面支架受载特征 .................................................................................................... 14 2.2.1 测点布置及监测方法 .............................................................................................. 14 2.2.2 支架载荷实测结果分析 .......................................................................................... 15 2.3 工作面矿山压力显现规律 ............................................................................................ 18 2.3.1 工作面走向矿山压力显现规律 .............................................................................. 18 2.3.2 工作面倾向矿山压力显现规律 .............................................................................. 22 2.4 工作面煤壁片帮现场观测与分析 ................................................................................ 24 2.4.1 煤壁片帮特征 .......................................................................................................... 24 2.4.2 煤壁片帮机理 .......................................................................................................... 25 2.4.3 煤壁片帮主要影响因素分析 .................................................................................. 26 2.5 本章小结 ........................................................................................................................ 31 3 大倾角大采高采场围岩活动规律相似材料模拟实验 ...................................................... 32 3.1 实验方法及力学参数 .................................................................................................... 32 3.2 实验监测手段及仪器 .................................................................................................... 32 3.3 沿工作面走向覆岩运动与煤壁稳定性特征 ................................................................ 33 3.4 沿工作面倾向覆岩活动与煤壁稳定性特征 ................................................................ 39 3.5 本章小结 ........................................................................................................................ 49 4 大倾角大采高采场围岩应力与位移特征数值分析 .......................................................... 50 4.1 数值计算模型建立 ........................................................................................................ 50 4.2 不同采高条件下采场围岩运移与力学演化规律 ........................................................ 50 万方数据 目 录 II 4.2.1 不同采高条件下围岩应力分布特征 ...................................................................... 50 4.2.2 不同采高条件下围岩位移分布特征 ...................................................................... 53 4.2.3 不同采高条件下围岩塑性破坏特征 ...................................................................... 55 4.2.4 采高与煤壁稳定性的关系 ...................................................................................... 55 4.3 不同倾角条件下采场围岩运移与力学演化规律 ........................................................ 57 4.3.1 不同倾角条件下围岩应力分布特征 ...................................................................... 57 4.3.2 不同倾角条件下围岩位移分布特征 ...................................................................... 59 4.3.3 不同倾角条件下围岩塑性破坏特征 ...................................................................... 63 4.3.4 不同倾角大采高煤壁受力特征 .............................................................................. 64 4.4 本章小结 ........................................................................................................................ 65 5 大倾角大采高工作面煤壁失稳机理分析 .......................................................................... 66 5.1 大倾角大采高工作面覆岩结构演化机理 .................................................................... 66 5.1.1 覆岩结构演化过程与特征 ...................................................................................... 66 5.1.2 覆岩结构的基本形态 .............................................................................................. 69 5.1.3 煤壁支承压力倾向分布规律及其影响因素分析 .................................................. 73 5.2 大倾角大采高工作面煤壁倾向失稳分析 .................................................................... 74 5.2.1 煤壁倾向力学分析 .................................................................................................. 74 5.2.2 煤壁倾向变形规律及其影响因素分析 .................................................................. 78 5.2.3 沿倾向不同区域支架围岩关系 .............................................................................. 81 5.3 大倾角大采高工作面煤壁垂向失稳分析 .................................................................... 83 5.3.1 煤壁铅垂方向力学模型 .......................................................................................... 83 5.3.2 煤壁倾向失稳区域及强度条件 .............................................................................. 85 5.3.3 煤壁失稳的临界载荷确定 ...................................................................................... 86 5.4 本章小结 ........................................................................................................................ 88 6 大倾角大采高工作面煤壁稳定性控制工程实践 .............................................................. 89 6.1 工程背景 ........................................................................................................................ 89 6.2 煤壁片帮防治原则 ........................................................................................................ 89 6.3 煤壁片帮防治方法 ........................................................................................................ 90 6.4 煤壁片帮防治措施 ........................................................................................................ 93 6.4.1 工作面“R-W-S-F”系统稳定性控制技术措施 ........................................................ 93 6.4.2 坚硬顶板超前预爆破技术措施 .............................................................................. 94 6.4.3 工作面煤壁超前预加固技术措施 .......................................................................... 98 6.4.4 小仰伪斜角度工作面布置措施 .............................................................................. 98 6.4.5 全时动态工作面矿压监测技术措施 ...................................................................... 99 万方数据 目 录 III 6.4.6 其它控制措施 .......................................................................................................... 99 6.5 煤壁稳定性控制效果 .................................................................................................. 100 6.6 本章小结 ...................................................................................................................... 101 7 结论与展望 ........................................................................................................................ 102 7.1 主要结论 ...................................................................................................................... 102 7.2 创新点 .......................................................................................................................... 103 7.3 研究展望 ...................................................................................................................... 103 致 谢 .................................................................................................................................... 105 参考文献 ................................................................................................................................ 106 附 录 .................................................................................................................................... 114 万方数据 主要符号表 IV 主要符号表 l工作面推进距离； L工作面长度； H煤层开采高度； lcr采场围岩非对称壳体结构沿倾向的剖面形态由非对称扁平拱转化为 非对称拱时相应的工作面推进距离； hcr工作面推进距离 lcr时覆岩冒落达到的最大高度； 煤层倾角； hs1工作面上区段煤柱塑性区宽度； hs2工作面下区段煤柱塑性区宽度； q“压力拱”ACB 之上覆岩层承受的载荷； 下滑矸石休止角； FAy’，FAz’，FBy’，FBz’ 分别表示倾向压力拱拱脚 A 和 B 处约束力； 垮落矸石的碎胀系数； V覆岩矸石垮落量； Vˊ覆岩矸石下滑充填量； zˊ1yˊ 倾向方向不同位置 yˊ处的走向拱拱高； lyˊ 倾向方向不同位置 yˊ处的走向拱跨长； FOzˊ，FOxˊ分别为走向“压力拱”拱脚 O 处的约束力； pz’y煤壁上部岩层作用载荷； qfu煤壁与顶板和底板间的摩擦力； qfd煤壁与顶板和底板间的粘结力； py底板法向载荷； k弹性地基系数； E煤体弹性模量； I煤体惯性矩； C1，C2，C3，C4，D1，D2，D3，D4分别为积分常数； P煤壁所受的支承压力； Q支架工作阻力； T基本顶岩块破断后的水平推力； Fs基本顶破断岩块摩擦力； qu基本顶上部岩层载荷； 万方数据 主要符号表 V qd冒落矸石支承载荷； Lu基本顶破断岩块长度； Ld岩块 B 的长度； LQ支架与铰接点 O 的距离； LP煤壁到铰接点 O 的距离； h基本顶厚度； qd工作面无矸石支承区域支架载荷； H0煤层厚度在铅垂方向的投影长度； H1护帮板在铅垂方向的投影长度； Py煤壁支承压力； q重力载荷； q1煤壁内部挤压载荷； q2护帮板作用载荷； C1，C2，C3和 C4积分常数； V工作面顶板总势能； U煤壁岩梁从基本状态过渡到后屈曲状态的弯曲应变能； W1煤壁支承压力 Py引起的外力势能； W2煤壁重力载荷 q 引起的外力势能； W3分布载荷 q1引起的外力势能； W4三角形载荷 q2引起的外力势能； 煤体的泊松比； am顶板结构的变形模态幅值； [σ]许用应力； γ 顶板容重； Πm、Π2、Π4分别表示泛函 Π 的 m 阶次项的余项、二阶变分和四阶变分； β、β1、β2、β3、β4、β5分别表示计算常量； MAB、MBC分别表示煤壁岩梁 AB 段和 BC 段的弯矩方程； F煤壁岩梁 C 截面处的约束力。 万方数据 1 绪 论 1 1 绪 论 1.1 选题背景及研究意义 随着我国煤炭开采向西部地区和深部区域转移，大倾角煤层开采的重要性日益凸 显，国内外诸多学者、科研院所、煤炭企业从上世纪 50 年代开始对大倾角煤层开采技 术、成套设备及岩层控制理论进行了持续性的研究与工程实践，基本实现了大倾角中厚 煤层综采工作面的安全生产，并进行了大倾角厚及特厚煤层综放开采、大采高开采技术 试验，并取得了一定进步。新疆是我国第十四个大型煤炭生产基地，大倾角厚煤层储量 丰富，且煤炭资源优质，研究此类煤层开采对当地经济发展，煤矿现代化建设，资源安 全高效开发等十分重要。 新疆焦煤集团2130矿25221工作面开采煤层厚度3.58 9.77 m， 倾角 36 46 ，是典型的大倾角厚煤层。工作面初期采用综放开采技术，但实际回采率 低、资源浪费严重。 大采高技术目前在缓倾斜或局部倾斜中厚煤层中应用广泛，但随着大采高技术、大 倾角煤层开采理论与技术的完善，以及适用于大倾角条件下大采高成套设备的研制，大 采高技术已成为我国大倾角厚煤层开采一个新的发展方向，2012 年，2130 矿井进行了 大倾角大采高开采试验，工作面安全度增强，资源回收率、回收效能大幅度提升。同时， 煤壁片帮和架前冒顶灾害频发，极大地制约了大倾角大采高工作面正常生产，使得大采 高技术优势降低，增加围岩控制难度，更容易衍生顶板漏冒、飞矸等二次灾害，严重威 胁矿井生产效率和人员安全。 受煤层赋存环境影响，大倾角大