综放松软窄煤柱沿空巷道顶板不对称破坏机制与调控系统

发布时间：2018-06-06 18:17

本文选题：综放开采 + 沿空巷道　；参考：《中国矿业大学(北京)》2017年博士论文

【摘要】：近年来,随着综放开采工艺不断完善及回采设备大型化、自动化程度提高,大型集约化综放开采已成为我国厚及特厚煤层高产高效安全开采的重要发展方向。大型综放开采在实现厚煤层资源高产高效开采的同时,与之相匹配的综放回采巷道必然面临着大断面、强烈采动影响、软弱厚煤顶等围岩控制难题,加之近年来为响应国家建设资源节约型矿井的号召,窄煤柱条件下的综放大断面沿空巷道工程越发普遍。大量现场工程实践发现,综放沿空巷道顶板沿铅垂方向显现不对称下沉破坏,沿水平方向显现不对称挤压变形破坏,且变形破坏的不对称性在大型综放开采和区段窄煤柱条件下趋于恶化,甚至可能引发恶性冒顶和支护失效损毁等事故,导致顶板失去控制和煤巷安全性低下。传统的综放沿空巷道顶板破坏机制及相应的控制理论与技术无法有效解决此类巷道围岩失稳问题,有针对性地开展深入系统研究已具有刻不容缓的必要性和紧迫性。本文以王家岭煤矿20103区段运输平巷为工程背景,基于综放沿空巷道围岩性质结构和受采动影响程度的不对称差异性,探索顶板煤岩和支护体不对称矿压显现及其与各影响因素之间的关联性;深究顶板煤岩体的失稳准则和判据及偏应力场时空演化规律,阐明顶板不对称破坏机制和控制方向;设计有效控制顶板不对称变形破坏的新型锚索桁架结构,揭示其矿压控制作用原理;探究顶板与锚索桁架之间的不对称调控关系和指标体系,形成综放沿空巷道顶板的新型锚索桁架控制系统。取得如下结论:(1)对综放沿空巷道顶板变形破坏特征进行现场调研,调研结果表明:综放沿空巷道顶板以巷道中心线为轴沿铅锤方向和水平方向呈不对称矿压显现特征,沿铅垂方向,靠煤柱侧顶板严重下沉乃至局部冒漏顶,直接顶与煤柱之间存在滑移、错位、嵌入、台阶下沉等现象;沿水平方向,顶板岩层水平运动剧烈,存在围岩错动形成的明显挤压破碎带,并导致了W钢带和钢筋托梁弯曲失效、金属网撕裂等现象;围岩变形破坏主要发生于巷道的靠煤柱侧顶角(45.2%)、靠煤柱侧巷道顶板(25.8%)、煤柱帮中上部(22.6%)3个位置。(2)采用钻孔窥视方法观测顶板内裂隙发育情况,结果表明:靠实体煤侧顶板裂隙多以浅部发育的横向裂隙及离层和错位为主,而靠煤柱侧顶板裂隙可分为浅部(0~3.0 m范围)横向裂隙/离层发育区和深部(4.9~12.3 m范围)走向裂隙发育区(局部区域裂隙完全贯通形成断裂破碎带);根据钻孔长度、倾斜角度及破碎区范围,确定基本顶断裂位置距采空区约为5.496~6.847 m。(3)对20103区段运输平巷围岩进行室内力学实验,评价其物理力学性能。2#煤层单轴抗压强度为13.89MPa,属于软弱煤层,表现出一定的塑性特征;直接顶砂质泥岩具有较高的抗压、抗剪、抗拉强度,岩层相对稳定;基本顶粉砂岩单轴抗压强度达到142.34MPa,稳定性较高;底板泥岩单轴抗压强度为44.64MPa,遇水泥化。(4)通过理论分析方法研究了综放沿空巷道基本顶结构特征及其与顶板不对称破坏的关系。理论计算确定了侧向基本顶的几何尺寸与破断位置,建立了综放开采侧向关键块破断结构模型,解算得出采动影响下沿空巷道顶板岩梁弯矩和挠度表达式;综放沿空巷道顶板弯矩和挠度均沿沿巷道中心线呈显著的不对称特征,最大弯矩和挠度出现在距煤柱帮1.5m处,该区域是顶板破坏的关键部位。(5)采用UDEC数值模拟软件分析沿空巷道基本顶运动与巷道围岩稳定性的关系,探讨基本顶破断位置与沿空巷道不对称矿压显现的定量关联性。浅部0~2.0m范围内靠煤柱侧顶板下沉量明显大于靠实体煤侧顶板下沉量,深部2.0~5.0m范围内顶板下沉量自实体煤侧到煤柱侧呈线性增大趋势;浅部0~1.5m范围内岩层从两侧向巷道内发生挤压运动,0水平位移点由巷道中心处向实体煤侧转移0.9m,深部1.5~6.0m范围内岩层由煤柱侧向实体煤侧发生运动。随着基本顶破断线与沿空巷道中心线距离减小或者基本顶下沉量增大,煤柱承受的垂直载荷逐渐增大,使得煤柱帮自身承载性能及其对顶板支撑作用明显弱于实体煤帮,从而加剧了沿空巷道围岩结构的不对称性和顶板变形破坏不对称性。(6)采用FLAC数值模拟软件分析综放开采不同阶段沿空巷道顶板岩层畸变能演化过程。综放沿空巷道顶板0~3.5m高度范围内偏应力第二不变量呈“双峰状”分布形态,3.5~11.5m高度范围内偏应力不变量呈“单峰状”分布形态;受本工作面回采期间上覆岩层二次破断影响,煤柱承载能力降低致使其上方顶板岩层畸变能存储能力降低,引起偏应力第二不变量峰值向实体煤上方顶板转移。随着煤柱宽度或强度减小,煤柱帮承载能力降低并发生压缩变形,造成靠煤柱侧顶板承载能力降低,顶板偏应力开始向实体煤上方顶板转移,并诱发了靠煤柱侧顶板沿垂直方向和水平方向的不对称位移。(7)基本顶结构回转下沉、松软煤柱帮、巷道大断面、支护不合理等是造成沿空巷道围岩性质结构和应力分布不对称性的主要因素。综放沿空巷道顶板不对称破坏灾变过程如下:相邻工作面推进→基本顶发生破断回转下沉运动→巷道附近区域煤岩体损伤→巷道开掘促使围岩性质结构和顶板应力的不对称分布→靠煤柱侧煤岩体(顶板、顶角、煤柱帮上部等)局部位移变形→靠煤柱侧顶板煤岩体大范围破碎或岩层错位、嵌入、台阶现象→支护结构载荷增大与不均匀受力→实体煤侧煤岩体位移变形→大规模围岩变形和支护体破坏→本工作面回采再次激活覆岩结构,不对称变形破坏进一步加剧。(8)基于综放沿空巷道顶板不对称破坏机制,提出了以“不对称式锚梁结构”为核心的综放沿空巷道调控系统,其主要包括高强锚杆、预应力桁架锚索和不对称式锚梁结构,该调控系统不但具有控制大范围塑性破坏、抗剪性能强的优点,且能对巷道顶板煤岩体变形的不对称性做出积极响应并能对其进行有效的控制;研发的以高强度钢筋托梁和16#槽钢托梁为连接构件的不对称锚梁结构,具有承压降载、减垮抗拉、不对称控制和适应顶板水平运动的特点。(9)结合20103区段运输平巷地质生产条件进行支护参数设计,并提出了现场控制思路。具体支护措施包括:(1)对顶板进行高强锚杆支护,控制围岩松动变形,保证顶板整体性和巷道作业环境安全;(2)煤柱帮高强锚杆支护,减少煤柱帮压缩变形,提高煤柱帮承载能力,降低顶板变形不对称程度;(3)顶板不对称式锚梁支护,提高靠煤柱侧顶板承载能力,抑制顶板不对称下沉和水平挤压变形;(4)顶角锚索补强加固,提高顶角煤岩稳定性,避免局部冒落失稳;(5)对超前采动影响范围内顶板和煤柱进行超前加固,进一步提高巷道稳定性。20103区段运输平巷现场工程实践表明,采用不对称锚梁支护系统后,巷道维护状况良好,未发生顶板冒漏现象,顶板不对称变形破坏得到有效控制,巷道断面满足工作面通风、运输、行人等要求。
[Abstract]:In recent years, with the continuous improvement of fully mechanized caving mining technology and the large-scale mining equipment, the degree of automation has been improved. The large intensive caving mining has become an important development direction for high yield and high efficiency and safety mining in thick and thick coal seam in China. The roadway must be faced with large section, strong mining influence, weak thick coal top and other surrounding rock control problems. In addition, in response to the call of the country to build a resource saving mine in recent years, the fully mechanized section along the Empty Roadway Project under the condition of narrow coal pillar is more common. A large number of field engineering practice found that the roof of the roadway along the roadway along the space along the vertical direction appears in the vertical direction. Asymmetric subsidence and destruction along the horizontal direction show asymmetric deformation and failure, and the asymmetry of deformation and failure tends to deteriorate under the condition of large caving mining and narrow section of coal pillar, and may even cause accidents such as malignant roof and support failure, which leads to the loss of control of the roof and the low safety of coal roadway. The failure mechanism of the roof and the corresponding control theory and technology can not effectively solve the problem of instability of the surrounding rock of this kind of roadway. It is necessary and urgent to carry out the thorough and systematic research on the roadway. This paper is based on the construction of the roadway of 20103 section of Wangjialing coal mine, based on the structure and mining of the surrounding rock of the roadway along the fully mechanized coal caving. The asymmetrical difference between the dynamic influence degree and the unsymmetrical ore pressure of the roof coal and the support body and the correlation with the influencing factors are explored, the instability criterion and the criterion and the spatio-temporal evolution of the partial stress field of the roof coal rock are studied, and the asymmetric failure mechanism and control direction of the roof are clarified, and the design of the roof asymmetry deformation is designed effectively. The new type of broken anchor cable truss structure reveals the principle of ore pressure control, explores the asymmetric regulation relationship and index system between the roof and the anchor cable truss, and forms a new type of anchor cable truss control system for the roof of the roadway along the goaf. The following conclusions are obtained: (1) field investigation and investigation on the deformation and failure characteristics of the roof of fully mechanized caving roadways The results show that the roof of the roadway along the roadway is asymmetrical ore pressure along the lead and horizontal direction of the roadway along the center line of the roadway. Along the vertical direction of the roadway, the roof of the coal pillar is heavily subsided by the side roof of the pillar, and there is a slip, the dislocation, the step subsidence and so on, and the level of the roof strata along the horizontal direction, and the level of the roof strata along the horizontal direction. Vigorous movement, there is an obvious extrusion crushing zone formed by the dislocation of the surrounding rock, which leads to the failure of the W steel belt and the reinforcement bracket, and the tear of the metal net. The deformation and damage of the surrounding rock mainly occurs in the side corner of the pillar of the coal pillar (45.2%), the roof of the coal pillar side roadway (25.8%), the upper part of the pillar (22.6%) 3 positions. (2) the drilling peep method is adopted. The fracture development in the roof is observed. The results show that the fracture of the roof of the solid coal side is mainly the transverse fissure and the displacement and dislocation in the shallow part, while the fracture of the side roof of the pillar can be divided into the shallow part (0~3.0 m range) and the depth (4.9~12.3 m range) to the fractured zone. According to the length of drilling, the angle of inclination and the scope of broken zone, it is determined that the basic roof fracture position is about 5.496~6.847 M. (3) to carry out the indoor mechanical experiment on the surrounding rock of the 20103 section transportation, and the physical and mechanical properties of the coal seam are evaluated as the single axis anti pressure degree of 13.89MPa, which belongs to the soft coal seam, and shows certain plasticity. The direct top sand mudstone has high compression, shear resistance and tensile strength, and the rock layer is relatively stable; the uniaxial compressive strength of the basic top siltstone is 142.34MPa and the stability is high; the uniaxial compressive strength of the floor mudstone is 44.64MPa and cemented. (4) through theoretical analysis, the basic roof structure characteristics and the top of the fully mechanized caving roadway are studied. The geometric size and breaking position of the lateral basic top are determined by theoretical calculation, and the broken structure model of the key block in fully mechanized mining side is established, and the expression of the bending moment and deflection of the roof of the roadway along the goaf is calculated, and the bending moment and deflection of the top plate along the roadway along the roadway are all along the center line of the roadway. The asymmetry characteristic, the maximum bending moment and deflection appear at the distance from the coal column 1.5m, and this area is the key part of the roof failure. (5) the relationship between the basic roof movement of the roadway along the empty laneway and the stability of the roadway surrounding rock is analyzed by UDEC numerical simulation software, and the quantitative correlation between the basic roof breaking position and the unsymmetrical ore pressure in the roadway along the empty roadway is discussed. The shallow 0~2. The subsidence of the side roof of the coal pillar in the range of 0m is obviously larger than that of the solid coal side roof. The subsidence of the roof in the deep 2.0~5.0m range is linearly increasing from the solid coal side to the pillar side, and the rock stratum in the shallow 0~1.5m ranges from both sides to the roadway, and the 0 horizontal displacement point is transferred from the center of the roadway to the solid coal side 0.9m, and the depth is deep. The rock stratum in the range of 1.5~6.0m is moved by the coal pillar to the solid coal side. The vertical load of the pillar gradually increases with the decrease of the basic top breaking line and the distance of the central line of the roadway along the goaf or the increase of the basic roof subsidence, which makes the bearing performance of the pillar and its supporting effect on the roof weaker than that of the solid coal. The asymmetry of the surrounding rock structure and the roof deformation are asymmetrical. (6) FLAC numerical simulation software is used to analyze the evolution process of the roof rock deformation of the roof of the roadway along the empty laneway in different stages of fully mechanized caving mining. The second invariants of the partial stress in the height range of the roof of the fully mechanized caving roadway are "Shuangfeng", and the height of the 3.5~11.5m is high. The internal partial stress invariants have a "single peak" distribution pattern, and the decrease of the bearing capacity of the coal pillar leads to the decrease of the storage capacity of the upper roof rock distortion and the shift of the peak stress of second unvariable to the top plate above the solid coal. As the width or strength of coal pillar decreases, the coal pillar is reduced by the two breakage of the overlying strata during the recovery period of the working face. The bearing capacity of the supporting capacity is reduced and the compression deformation occurs, which leads to the reduction of the bearing capacity of the side roof of the pillar, the partial stress of the roof begins to transfer to the top roof of the solid coal, and induces the asymmetrical displacement of the side roof along the vertical direction and the horizontal direction. (7) the basic roof structure is slewing down, the soft coal column, the roadway large section and the support are unreasonable, etc. It is the main factor that causes the asymmetry of the nature structure and the stress distribution of the surrounding rock along the goaf. The catastrophe process of the asymmetry failure of the roof of the roadway along the roadway is as follows: the adjacent working face's propulsion, the basic roof, the broken and turning subsidence movement, the damage of the coal and rock in the vicinity of the roadway, and the opening of the roadway impel the nature structure of the surrounding rock and the roof stress. The local displacement and deformation of the coal rock mass (roof, top angle, upper part of coal pillar) of the coal pillar (roof, top angle, upper part of coal pillar) is broken in large scope or the dislocation of the rock layer on the side roof of the coal pillar, and the step phenomenon, the load of the supporting structure and the deformation of the coal and rock mass of the solid coal to the solid coal side, the deformation of the mass surrounding rock and the failure of the support of the supporting body. At the working face, the overlying rock structure is reactivated again, and the asymmetric deformation is further aggravated. (8) based on the asymmetric failure mechanism of the roof of the roadway along the fully mechanized caving, the control system with the core of the "asymmetric anchor beam structure" is put forward, which mainly includes the high strength bolt, the prestressed truss anchor cable and the asymmetric anchor beam structure. The control system not only has the advantages of controlling large plastic damage and strong shearing resistance, but also can respond positively to the asymmetry of roadway roof coal rock deformation and can control it effectively. The unsymmetrical anchor beam structure with high strength steel bar bracket and 16# channel beam as the connecting member has pressure reduction load and collapse resistance. Pull, asymmetric control and adapt to the characteristics of the horizontal movement of the roof. (9) combined with the 20103 section of the roadway geological production conditions for support parameters design, and put forward the idea of field control. Specific support measures include: (1) high strength bolt support to the roof, control of the surrounding rock deformation, to ensure the integrity of the roof and the safety of roadway operation environment; 2) coal pillar to help high strength bolt support, reduce coal pillar compression deformation, improve the bearing capacity of coal pillar and reduce the asymmetry of roof deformation; (3) roof asymmetric anchor beam support, improve the bearing capacity of coal pillar side roof, restrain the roof asymmetry subsidence and horizontal extrusion change; (4) top angle anchorage reinforcement to improve the stability of top angle coal rock, avoid the stability of roof angle coal rock. There is no local caving and instability; (5) advance reinforcement of roof and pillar in the influence range of advanced mining, and further improving the field engineering practice of roadway stability in.20103 section, it shows that the roadway maintenance condition is good, no roof leakage phenomenon occurs, and the asymmetry deformation and failure of roof can be effectively damaged after the use of the unsymmetrical anchor beam supporting system. Control, roadway section to meet ventilation, transportation, pedestrians and other requirements.
【学位授予单位】：中国矿业大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD322;TD353

【参考文献】