巷道围岩离层下锚杆荷载传递机理及支护设计研究.pdf
Research on Bolt Load Transfer Mechanism Under Bed Separation Effect and Its Support Design Dissertation ted to Xi’an University of Science and Technology In Partial Fulfillment of the Requirement For the Degree of Doctor of Engineering By Ding Xiao School of Architecture and Civil Engineering Dissertation Directed by Professor Gu Shuancheng June,,2016 万方数据 学 位 论 文 独 创 性 说 明 本人郑重声明 所呈交的学位论文是我个人在导师指导下进行的研究工作及其取得 研究成果。尽我所知,除了文中加以标注和致谢的地方外,论文中不包含其他人或集体 已经公开发表或撰写过的研究成果, 也不包含为获得西安科技大学或其他教育机构的学 位或证书所使用过的材料。 与我一同工作的同志对本研究所做的任何贡献均已在论文中 做了明确的说明并表示了谢意。 学位论文作者签名 日期 学 位 论 文 知 识 产 权 声 明 书 本人完全了解学校有关保护知识产权的规定,即研究生在校攻读学位期间论文工 作的知识产权单位属于西安科技大学。 学校有权保留并向国家有关部门或机构送交论文 的复印件和电子版。本人允许论文被查阅和借阅。学校可以将本学位论文的全部或部分 内容编入有关数据库进行检索,可以采用影印、缩印或扫描等复制手段保存和汇编本学 位论文。同时本人保证,毕业后结合学位论文研究课题再撰写的文章一律注明作者单位 为西安科技大学。 保密论文待解密后适用本声明。 学位论文作者签名 指导教师签名 年 月 日 万方数据 论文题目巷道围岩离层下锚杆荷载传递机理及支护设计研究 专 业岩土工程 博 士 生丁 潇 (签名) 指导教师谷拴成 (签名) 摘 要 随着煤矿生产规模的不断扩大以及大型机械设备的广泛使用,为满足生产运输要 求,煤矿巷道断面尺寸随之不断增大。由于煤矿巷道顶板多为层状沉积岩,巷道尺寸增 大会使围岩产生较大变形,在顶板处易产生离层,由此引发的巷道支护问题亟待解决。 传统的支护设计方法均将围岩视为连续均质介质,未考虑离层的不利影响,本文在分析 和总结现有锚固支护理论、锚固界面力学机理研究现状及存在问题的基础上,考虑锚固 支护岩体的复杂性,特别是层状岩体中巷道开挖引发的离层对锚杆荷载传递规律的影 响,利用理论分析、现场试验及数值模拟等方法,开展了以下几方面的研究。 基于离层的产生机理对离层进行分类,分析巷道离层型顶板的特征,给出离层位置 和离层值的理论估算方法及试验确定方法。 根据柠条塔 N1205 工作面地质条件, 对离层 位置及离层值大小进行综合判断,为考虑离层条件下的锚杆支护设计打下基础。 分析离层作用下的锚杆荷载传递机理,基于剪切滑移模型,分别建立单离层条件下 垂直锚杆和倾斜锚杆,以及多离层条件下锚杆荷载传递的弹塑性力学模型,得出离层作 用下锚杆应力分布的表达式,总结出离层发展过程中锚杆荷载的变化规律,并对不同离 层值、离层位置、锚杆与离层夹角等参数影响下的锚杆受力特性做系统分析。 设计室内模型试验,研究离层对锚杆的荷载作用,得出岩体裂缝扩展过程中锚杆的 应力分布规律及裂缝张开量值与杆体荷载的关系, 将试验结果与理论计算值进行对比分 析,验证理论模型的正确性及适用性。运用二维离散元软件对非均质岩体中锚杆的受力 状态进行数值模拟,并对影响参数进行规律性分析。 分别建立考虑离层影响的全长粘结型锚杆以及局部锚固锚杆的力学模型, 对系统锚 杆进行受力分析,综合理论计算和数值模拟结果,分析获得离层岩体中锚杆的荷载分布 规律。通过系统锚杆荷载求解,对已有的锚杆支护设计进行安全性评价,并为含有离层 情况的锚杆支护设计提供理论依据。 将研究成果应用于陕北柠条塔煤矿 N1205 工作面胶运顺槽支护设计中, 对比传统的 支护设计方法,发现考虑离层影响后的锚杆荷载超过承载力设计值,原有的支护参数不 能满足安全要求,需对参数进行调整,通过系统锚杆荷载求解,对锚杆直径、间排距及 万方数据 锚固长度进行重新设计,并对预紧力的合理取值进行讨论。现场监测结果表明考虑离层 情况的锚杆支护设计方法更安全合理。 关 键 词巷道;层状岩体;离层;锚杆荷载;支护设计;预紧力 研究类型应用基础研究 万方数据 Subject Research on Bolt Load Transfer Mechanism Under Bed Separation Effect and Its Support Design Specialty Geotechnical Engineering Name Ding Xiao ((Signature)) Instructor Gu Shuancheng ((Signature)) ABSTRACT With the continual expansion in the production scale of coal mine and the wide use of large mechanical equipment, roadway section has been increased to meet the requirements of production and transportation. Coal mine roadway roof is mostly layered by the sedimentary rock. Large cross-section produces large surrounding rock deation, and bed separation occurs easily, thus initiated problem of roadway support has to be solved. Surrounding rock was regarded as continuous homogeneous medium in the traditional supporting design, and the negative impact of the bed separation was not considered. Following the research of current anchoring theory and the status and existing problems of the mechanical mechanism of anchorage interface, the complexity of rock mass that is anchorage supported was considered in this paper, especially the effect of bed separation caused by underground excavation. The research has been done in the following aspects. The bed separation was classified based on its generation mechanism. Following the characteristic analysis of roof separation layer, the location and value of the bed separation were judged by theoretical and test . Combined with the geological conditions of roadway of the N1205 working face in Ning tiaota Coal Mine, the location and value of the bed separation can be judged comprehensively, which provides a basis for anchorage support. Load transfer mechanism of bolt affected by bed separation was analyzed. Through the shear slide model, the elastic-plastic load transfer model was obtained under the different conditions of vertical and inclined bolt in single separation layer and multiple separation layers. ulas of bolt stress distribution and load variation in the development of bed separation were gained. The bolt mechanical characteristics were obtained under the conditions of different bed separation values, location and angle. Laboratory model test was designed in order to observe the bolt stress distribution in the crack propagation of rock mass and the relationship between bolt load and the amount 万方数据 of crack opening. Comparing with the theoretical analysis, the correctness and applicability of the theoretical model were verified. 2D discrete element simulation analysis was carried out on the bolt element under heterogeneous condition. The parameter influence law of the bed separation value and position were summarized, which was consistent with the theory. The effect of bolt loading caused by bed separation was considered in fully grouted bolt and end anchoring-grouting bolt, and the mechanics models were established respectively. According to the theoretical calculation and numerical simulation results, the stress distribution of bolt in the rock mass which has bed separation was achieved. Through the solving of systematic bolt load, the safety of the existing bolt support design can be uated, which also can provide the basis for supporting design. Achievements all above were applied in roadway supporting design of the N1205 working face in Ning tiaota Coal Mine. Compared with the traditional design , the analysis revealed bolt load has exceeded the bearing capacity design value, so it is neccessary to adjust the design parameter of the support in order to ensure the safety of the design and construction. Through the solving of systematic bolt load, the diameter, interval and anchorage length of bolts were redesigned, then the reasonable pre-tension load was discussed. Field monitoring results showed that the supporting design considered the effect of bed separation was more safe and reasonable. Key words Roadway Layered Rock Mass Bed Separation Bolt Load Support Design Pre-tension Thesis Application Fundamental Research 万方数据 目 录 I 目 录 1 绪论 ........................................................................................................................................ 1 1.1 选题背景与研究意义 ................................................................................................. 1 1.2 国内外发展现状 ......................................................................................................... 2 1.2.1 锚杆支护研究现状 .......................................................................................... 2 1.2.2 岩土锚固作用机理研究现状 .......................................................................... 3 1.2.3 锚杆荷载传递理论研究现状 .......................................................................... 6 1.3 研究内容与研究方法 ............................................................................................... 13 2 巷道离层型顶板的特征分析 .............................................................................................. 15 2.1 离层的概念及产生机理 ........................................................................................... 15 2.1.1 离层的定义及分类 ........................................................................................ 15 2.1.2 离层产生的机理分析 .................................................................................... 16 2.1.3 影响顶板离层的主要因素 ............................................................................ 16 2.1.4 锚杆对离层作用分析 .................................................................................... 17 2.2 离层位置及离层值的确定方法 ............................................................................... 18 2.2.1 离层的理论估算方法 .................................................................................... 18 2.2.2 离层的试验确定方法 .................................................................................... 22 2.3 本章小结 ................................................................................................................... 30 3 离层对锚杆作用荷载理论分析研究 .................................................................................. 31 3.1 单离层条件下锚杆作用荷载分析 ........................................................................... 31 3.1.1 单离层垂直锚杆弹性模型建立 .................................................................... 31 3.1.2 单离层垂直锚杆弹塑性模型建立 ................................................................ 34 3.1.3 锚杆合理孔径比确定 .................................................................................... 49 3.1.4 倾斜锚杆受离层作用分析 ............................................................................ 50 3.2 多离层条件下锚杆作用荷载分析 ........................................................................... 56 3.3 离层对锚杆作用荷载数值模拟 ............................................................................... 59 3.3.1 二维离散元 UDEC 介绍 ............................................................................... 59 3.3.2 离层试块数值模拟 ........................................................................................ 60 3.3.3 计算结果参数分析 ........................................................................................ 65 3.4 本章小结 ................................................................................................................... 66 4 离层对锚杆作用荷载试验研究 .......................................................................................... 67 4.1 试验目的 .................................................................................................................... 67 4.2 试件设计 .................................................................................................................... 67 万方数据 目 录 II 4.2.1 试件形状 ......................................................................................................... 67 4.2.2 试验材料及尺寸 ............................................................................................. 68 4.2.3 构造要求 ......................................................................................................... 69 4.2.4 试件制作 ......................................................................................................... 69 4.3 辅助试验 .................................................................................................................... 72 4.3.1 锚杆性能试验 ................................................................................................. 72 4.3.2 锚固力测试试验 ............................................................................................. 72 4.4 试验方案 .................................................................................................................... 75 4.4.1 试验加载装置及加载制度 ............................................................................. 75 4.4.2 观测方案 ......................................................................................................... 76 4.4.3 测试结果分析 ................................................................................................. 77 4.5 本章小结 ................................................................................................................... 81 5 考虑围岩离层影响的系统锚杆荷载分析 .......................................................................... 83 5.1 全长粘结型锚杆系统分析 ....................................................................................... 83 5.1.1 理论模型建立 ................................................................................................ 83 5.1.2 无离层情况下锚杆与围岩相互作用 ............................................................ 84 5.1.3 考虑离层因素的锚杆受力分析 .................................................................... 84 5.1.4 全长粘结型锚杆数值模拟 ............................................................................ 87 5.2 局部锚固锚杆系统分析 ........................................................................................... 92 5.2.1 理论模型建立 ................................................................................................ 92 5.2.2 预紧力单独作用下的锚固段应力分布 ........................................................ 93 5.2.3 考虑围岩作用的预应力锚杆受力分析 ........................................................ 93 5.2.4 考虑离层情况的预应力锚杆受力分析 ........................................................ 95 5.2.5 局部锚固锚杆数值模拟 ................................................................................ 97 5.3 系统锚杆支护安全性评价 ..................................................................................... 101 5.3.1 评价依据 ...................................................................................................... 101 5.3.2 算例分析 ...................................................................................................... 102 5.4 本章小结 ................................................................................................................. 105 6 巷道围岩离层下锚杆支护设计及应用 ............................................................................ 107 6.1 考虑离层作用的支护设计方法 ............................................................................. 107 6.2 工程概况 ................................................................................................................. 109 6.3 通过拉拔试验确定抗剪强度参数 ......................................................................... 109 6.3.1 理论分析 ...................................................................................................... 109 6.3.2 拉拔荷载试验 .............................................................................................. 111 万方数据 目 录 III 6.4 考虑离层影响的巷道支护设计 ............................................................................. 114 6.4.1 锚固范围内离层值预估 .............................................................................. 114 6.4.2 考虑离层影响的巷道支护参数设计 .......................................................... 115 6.4.3 锚杆预紧力讨论分析 .................................................................................. 118 6.5 巷道支护效果对比评价 ......................................................................................... 119 6.6 本章小结 ................................................................................................................. 121 7 结论与展望 ........................................................................................................................ 122 7.1 主要结论 ................................................................................................................. 122 7.2 主要创新点 ............................................................................................................. 123 7.3 展望 ......................................................................................................................... 124 致 谢 .................................................................................................................................... 125 参考文献 ................................................................................................................................ 126 附 录 .........................................................................................