大跨度穿断层软岩巷道顶板非对称破裂机制与控制对策研究  

Study on asymmetric fracture mechanism and control strategy of soft rock roadway roof with large span section and crossing fault

作　　者：李冲[1,2] 何思锋[1,2] 陈梁 LI Chong;HE Sifeng;CHEN Liang(School of Mines,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;Key Laboratory of Deep Coal Resource Mining,Ministry of Education,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China)

机构地区：[1]中国矿业大学矿业工程学院,江苏徐州221116 [2]中国矿业大学深部煤炭资源开采教育部重点实验室,江苏徐州221116 [3]中国矿业大学煤炭资源与安全开采国家重点实验室,江苏徐州221116

出　　处：《采矿与安全工程学报》2021年第6期1081-1090,共10页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(51874277)。

摘　　要：针对大跨度穿断层软岩巷道顶板非对称大变形失稳的工程难题,总结分析原支护条件下巷道变形破坏特征及其主控影响因素,给出基于MATLAB图像处理技术的钻孔裂隙发育程度定量表征方法,模拟研究巷道顶板位移场、主应力场及裂隙场演化规律,揭示巷道顶板渐进非对称破裂机制;根据不同区域巷道变形破坏情况与离散模拟结果,针对性地提出顶板"非对称分区强化控制、减跨控顶支护、破碎围岩分区深浅注浆、强化联合支护"的过断层支护对策,优化支护方案并进行现场应用。研究结果表明:1)巷道顶板破坏深度、变形特点、破裂模式等均呈现明显的非对称变化特征,断层左侧(Ⅰ区)及右侧(Ⅱ区)顶板裂隙密度均随巷道表面至深部距离变化呈负对数衰减特点,后者数值较大且降速较快,表明Ⅱ区顶板整体较为破碎且破坏深度较广,应为重点控制对象;2)巷道开挖至稳定过程中,Ⅱ区浅部围岩首先发生张拉破坏,并伴随大量裂隙的萌生与扩展,然后左帮顶角位置因应力集中也出现裂隙密集区且逐渐向顶板断层部位延伸,而后顶板表面裂隙均随开挖时间的增加向深部非对称渐进扩展,浅部离层发生并伴随局部块体脱落,顶板发生非对称冒落失稳;3)采用优化支护方案后,顶板最大变形量低于91mm,较原支护降低了63.89%;浆液与破碎岩体黏结形成复合结构,围岩完整性提高;锚杆受力最大值为81.76 kN,最小值为60.5 kN,分别为屈服载荷的43%和31.8%,基本满足工程需求。Regarding the large deformation instability of crossing fault in soft rock roadway with large span section,the deformation characteristic of surrounding rock and main factors affecting roadway deformation were comprehensively analyzed for the origin support condition.A quantitative characterization method of fracture propagation degree in borehole was also presented using the MATLAB image processing techniques.Then,the evolution law of displacement,principal stress and crack fields of crossing fault roof were discussed for revealing the gradual asymmetric failure mechanism of the roof.Finally,a new crossing fault support technology was proposed,which is the"Asymmetry section tighten control,decrease span combined with strengthening control roof,section grouting of fracture surrounding rock considering various grouting depths,combination support system".The optimized support approach was introduced and applied to industrial tests.Research results indicate that:1)The fracture depth,deformation characteristic and fracture model of roadway roof showed obvious asymmetric characteristics.The crack density on the left(zone I)and right(zone II)sides of the roof fault exhibited negative logarithmic attenuation characteristic with the distance from the roadway surface to the depth.However,the crack density value in zone II was significantly higher than that in zone I,indicating that the roof in zone II was generally broken compared with that in zone I.Thus,zone II should be the key support object.2)During roadway excavation,the tensile failure in shallow surrounding rock of zone II occurred first with the crack initiation and expansion.Meanwhile,numerous cracks at left shoulder in zone I also began to appear due to the stress concentration,and then gradually extended to roof fault location.Next,all the cracks in the roof surface gradually extended to the deep asymmetrically as excavation time increases.The shallow separation and block drop phenomenon began to appear,which would induce asymmetric caving instability of roadw

关 键 词：穿断层软岩巷道 非对称失稳 裂隙密度 定量表征 围岩控制 

分 类 号：TD353[矿业工程—矿井建设]