高应力软岩回采巷道预应力锚杆——锚索支护技术研究.pdf

武汉理工大学博士学位论文 申请申请工学博工学博士学位论文士学位论文 高应力软岩回采巷道预应力锚杆高应力软岩回采巷道预应力锚杆 锚索支护技术研究锚索支护技术研究 培养单培养单位位土木工程与建筑学院土木工程与建筑学院 学科专学科专业业岩土岩土工程工程 研 究研 究 生生白启树白启树 指导老指导老师师夏元友夏元友 研究员研究员 2014 年 3 月 高 应 力 软 岩 回 采 巷 道 预 应 力 锚 杆 高 应 力 软 岩 回 采 巷 道 预 应 力 锚 杆 锚 索 支 护 技 术 研 究 锚 索 支 护 技 术 研 究 白 启 树 白 启 树 武 汉 理 工 大 学 武 汉 理 工 大 学 万方数据 分类号分类号 密密 级级 UDC 学校代码学校代码 10497 学学 位位 论论 文文 题 目 高应力软岩回采巷道预应力锚杆锚索支护技术研究 英 文 Research on the support technology of pre-stressed cable 题 目 anchor in high stress soft rock coal roadway 研究生姓名 姓名 职称 学位 单位名称 武汉理工大学 邮编 430070 姓名 职称 学位 单位名称 邮编 申请学位级别 博士 学科专业名称 论文提交日期 2014.3 论文答辩日期 2014.5 学位授予单位 武汉理工大学 学位授予日期 答辩委员会主席 评阅人 指导教师 副指导教师 万方数据 武汉理工大学博士学位论文 万方数据 武汉理工大学博士学位论文 万方数据 万方数据 武汉理工大学博士学位论文 独独 创创 性性 声声 明明 本人声明， 所呈交的论文是本人在导师指导下进行的研究工作及 取得的研究成果。 尽我所知， 除了文中特别加以标注和致谢的地方外， 论文中不包含其他人已经发表或撰写过的研究成果， 也不包含为获得 武汉理工大学或其他教育机构的学位或证书而使用过的材料。 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作了明确的说 明并表示了谢意。 签 名 日 期 学位论文使用授权书学位论文使用授权书 本人完全了解武汉理工大学有关保留、使用学位论文的规定，即 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， 允许论文被查阅和借阅。 本人授权武汉理工大学可以将本学位论文的 全部内容编入有关数据库进行检索，可以采用影印、缩印或其他复制 手段保存或汇编本学位论文。 同时授权经武汉理工大学认可的国家有 关机构或论文数据库使用或收录本学位论文， 并向社会公众提供信息 服务。 （保密的论文在解密后应遵守此规定） 研究生（签名） 导师（签名） 日期 注此页内容装订在论文扉页 万方数据 I 中文摘要 煤炭作为我国主要能源在国民经济中占据主足轻重的地位。煤矿回采巷道 支护技术作为煤矿生产中的关键一环，如何降低成本、提高工效、减少维护是 摆在我们面前的主要课题，目前大型矿井中 80以上都是煤巷，随着我国煤矿 开采强度与规模的不断增大和现代化综合机械化程度的大幅度提高，厚煤层综 采放顶煤开采、综采一次性采全高等要求巷道的断面要求越来越大。随着煤矿 开采水平的不断加深，高应力软岩巷道支护问题越来越突出，近些年来，锚网 索支护技术己成为大断面回采巷道的主要方式。它具有支护强度大、成本低等 许多优点，锚网索应用为解决大断面煤层回采巷道支护问题提供了一种有效方 法。然而，预应力锚网索支护理论研究远落后于工程实践，特别是对于预应力 锚杆与锚索联合支护高应力软岩回采巷道的变形特性还未见报道，为此，论文 以马临煤矿 C8 煤层回采巷道支护问题为背景，针对高应力软岩回采巷道的流变 问题，开展回采巷道围岩变形特征和破坏机理研究，通过流变试验，建立回采 巷道锚杆与围岩支护流变本构模型，利用 FLAC3D 数值模拟，研究不同预紧力 锚杆与锚索支护高应力软岩回采巷道的变形机理。并将研究成果应用于高应力 软岩支护巷道中。通过研究取得了以下成果 1）基于泥质粉砂岩常规三轴压缩试验，通过建立不同围压对软岩峰后软化 的力学模型，研究不同围压下泥质粉砂岩的峰后应变软化特征。以广义粘聚力c 和广义内摩擦角来表征的软岩后继屈服面模型， 并利用莫尔应力圆确定不同等 效塑性剪切应变 ps  和不同围压 3  条件下广义粘聚力c和广义内摩擦角。 2）依据软岩三轴压缩的分级加载蠕变试验曲线的规律与时效特征，建立了 高应力下泥质粉砂岩Burgers粘弹性流变模型， 并依据粘弹塑性力学的基本理论， 推导了该模型的一维蠕变本构方程，进而借助非线性回归分析辨识了模型参数。 对巷道围岩流变分析，得出了巷道围岩位移的粘弹性解，分析了围岩变形与应 力、巷道半径、岩性及支护体之间的关系。 3）运用 Monte-Carlo 随机数生成方法对回采巷道结构面进行网络模拟，从 而对岩体质量进行评价，在此基础上提出回采巷道岩体力学参数估算方法。给 出了回采巷道岩体力学参数建议值。 4）通过建立高应力软岩回采巷道锚杆锚索与围岩联合支护三维流变本 构模型，分析预应力锚杆锚索与围岩的作用机理。采用有限差分数值计算 万方数据 II 软件 FLA C3D 对高应力软岩回采巷道应力场和位移场进行数值模拟，系统研究 高垂直应力和高水平应力作用下软岩巷道锚杆索施加不同预紧力组合时围岩 产生的应力场分布特征；不同锚杆间距回采巷道围岩应力场分布特征。给出了 围岩变形、应力随着时间推移的变化规律。 5研究了不同支护强度、预紧力对高应力软岩巷道围岩的控制作用，揭示了 高应力软岩巷道围岩初期变形破坏具有不可克服性，建立了支护体让压支护的 力学模型，分析了不同自由让压距离和不同极限变形量对让压支护效果的影响。 6）开展高应力软岩回采巷道预应力锚杆与锚索协调支护研究，提出了预应 力锚杆、锚索协调支护的理念，通过预应力锚杆与锚索联合支护形成的组合拱 构建了巷道“次生承载层” ，从而实现对高应力软岩回采巷道预应力锚杆与锚索 联合支护参数优化。研究结果表明合理的支护密度，必须确保锚杆群支护产 生压应力区连成整体并相互叠加形成组合拱对顶板起支撑作用；在支护密度一 定时，锚杆的长度是确保锚杆形成的次生承载层的稳定，锚杆长度增加不会改 变巷道的支护效果，锚杆长度只需满足顶板形成组合拱的厚度。 6）针对高应力软岩回采巷道支护技术存在的问题，将研究成果应用于马临 矿 2083 回采巷道，通过现场观测，该支护体系能有效地控制回采巷道围岩变形 和蠕变，巷道的稳定性大大提高。 关键词关键词 高应力软岩，回采巷道；流变；预应力锚杆锚索；让压支护 万方数据 III Abstract Coal, the main energy of our country, plays a decisive role in our national economy. The support technology of mining gateway is regarded as a key link of coal mine production. So, how to reduce cost and raise efficiency is an important issue which we are confronted. Nowadays 80 percent of large-scale mines are coal roadway. With the increase of mining intensity and mechanization degree for coal mine in our country, the roadway section which is required by fully mechanized top-coal caving in thick coal seam and the fully mechanized single mine full-height become large and large,. Moreover, with the improvement of coal mining technology, the supporting problem of high stressed soft rock roadway is becoming more and more outstanding. In recent years, the bolt-mesh-cable supporting technology has been the main in roadway of large section. As this has large supporting strength, low cost and a number of other advantages, the application of bolt-mesh-cable provide an effective approach to solve large section gateway supporting problems. However, pre-stressed bolt-mesh-cable theoretical research was far behind the engineering practice. Especially, the deation characteristics for combined support of pre-stressed anchor and anchor rope in high stressed soft rock roadway has not been reported. Therefore, with the support problem of Malin coal mine C8 seam gateway as the background, aiming at the rheological problem of high stressed soft rock roadway, the study of surrounding rock deation features and failure mechanism was carried out in this paper. The rheological constitutive models of roadway bolt and surrounding rock was established by rheological test. Using FLAC3D numerical simulation software, the deation mechanism of high stress soft rock roadway under different pre-tightening force of anchor and anchor rope was studied, and the results were applied to the high stress roadway supporting system. The following innovative studied results were obtained 1）Based on the result of argillaceous siltstone conventional triaxial compression test, the post-peak strain softening characteristic of argillaceous siltstone at different confining stress was studied by establishing the mechanical model of post-peak softening soft rock at different confining stress. The soft rock subsequent yield 万方数据 IV surface model was characterized by the generalized cohesionc and the generalized internal friction angle. Besides, the generalized cohesionc and the generalized internal friction angle  at different equivalent plastic shear strain ps  and different confining stress were determined by Mohrs stress circle. 2 According to the law curve and time-dependent properties, which had been obtained by the soft rock graduation loading triaxial compression creep test, Burgers viscoelasticity rheologic model of argillaceous siltstone at high-stress situation was established. On the basis of viscoelastic plasticity mechanics theory, the one-dimensional creep constitutive equation this model was derived, and than the model parameters were identified with the help of non-line regression. By analyzing the surrounding rock rheological properties of roadway, the viscoelastic solution of surrounding rock displacement was obtained, and the relationship among the surrounding rock deation and stress, roadway radius, rock characteristics and supporting system was studied. 3 Using Monte-Carlo generating random number to simulate the structural plane of gateway with network, the rock mass quality was estimated. Furthermore, on the basis of this mehcod, the rock mechanics parameters estimation of gateway was proposed, and the suggested values for gateway rock mechanics parameters were given. 4 By establishing the three-dimensional rheological constitutive model of bolt-cable combination support for high stressed soft rock roadway, the mechanism of action for pre-stressed bolt-cable and surrounding rock was analyzed. The displacement field and stress field in high-stress soft rock gateway were simulated by finite difference numerical software FLAC3D. The stress field distribution features caused by different pre-stress combination which was rted by bolt or bolt-cable at soft rock roadway under the condition of high vertical stress and horizontal stress was studied. The rock stress field distribution features of roadway at different distance among bolts was also studied, and the law of surrounding rock deation and stress changed with time was given. 5The control action at different support intensity for the high stress soft rock roadway was studied using numerical simulation. The result shows that the initial deation of high stress soft rock roadway was insurmountable. So the “yield 万方数据 V pressure support“ is proposed. The yield pressure support mechanics model was established, and the support effects influenced by different yield distance and different limited deation amount was analyzed. 6 The idea of the secondary load bearing layer which was constructed by the compound arch composed of bolt-cable combination support was proposed. Moreover, the coordination of prestressing force for bolt-cable combination support was proposed. The parameter optimization of bolt-cable combination support for high stressed soft rock roadway was achieved. The research results indicate that The generated compressive zone of bolts group support should connect and overlap to a whole and than made up the arch structure which function was to sustain the roof must be guaranteed by rational supporting density. Bolts’ length was an element to make the secondary bearing stratum steadiness. When supporting density was fixed, the increase of the bolt length will not affect the bolt supporting effect, and the bolts length only required to satisfied the thickness of compound arch which s at roadway roof. 7 Aiming at the existent problems of high-stress soft rock gateway supporting technology, the research achievements was applied to 2083 gateway of Malin colliery. Through made field measurement, the gateway surrounding rock deation and creep were controlled by this supporting system effectively, and the roadway stability increased sharply. Key words gateway of soft rock; rheology; pre-stressed bolt-mesh-cable; yield stress support 万方数据 i 目目 录录 第第 1 章章 绪论绪论 .............................................................................................................. 1 1.1 引言 ................................................................................................................ 1 1.2 国内外研究现状 .............................................................................................. 2 1.2.1 巷道支护理论研究现状 ........................................................................ 2 1.2.2 预应力锚杆（索）支护作用机理研究发展现状 ................................ 3 1.2.3 软岩流变特性试验与理论研究 ............................................................ 4 1.2.4 软岩巷道流变特性研究 ........................................................................ 5 1.2.5 存在的问题 ............................................................................................ 6 1.3 论文的主要研究内容 ...................................................................................... 7 第第 2 章章 软岩峰后软化力学特性与流变特性研究软岩峰后软化力学特性与流变特性研究 .................................................. 9 2.1 软岩的分类及工程性质 ................................................................................. 9 2.1.1 软岩的定义 ............................................................................................ 9 2.1.2 软岩的分类 ............................................................................................ 9 2.1.3 软岩的工程特性和力学特性 .............................................................. 10 2.2 泥质砂岩三轴压缩试验 ................................................................................ 10 2.3 软岩峰后应变软化力学模型 ........................................................................ 11 2.3.1 峰后岩体后继屈服面模型 .................................................................. 12 2.4 软岩流变试验与流变模型研究 .................................................................... 14 2.4.1 C8 煤层泥质粉砂岩流变试验 ............................................................. 15 2.4.2 泥质粉砂岩蠕变模型建立 .................................................................. 16 2.4.3 流变模型参数的辨识方法 ................................................................. 17 2.5 本章小结 ........................................................................................................ 20 第第 3 章章 巷道岩体结构特征与岩体力学参数估算巷道岩体结构特征与岩体力学参数估算 ................................................ 21 3.1 概述 ................................................................................................................ 21 3.2 巷道岩体结构特征与结构面网络模拟 ........................................................ 21 3.3 回采巷道顶板力学参数估算 ....................................................................... 30 3.3.1 巷道顶板岩石强度参数 ..................................................................... 30 3.3.2 岩体的质量评价 ................................................................................. 33 3.3.3 岩体力学参数估算 .............................................................................. 34 万方数据 ii 3.3.4 巷道顶板力学参数 .............................................................................. 36 3.4 本章小结 ....................................................................................................... 36 第第 4 章章 回采巷道预应力锚杆回采巷道预应力锚杆锚索支护机理研究锚索支护机理研究 ............................................ 38 4.1 预应力锚杆与锚索联合支护机理 ................................................................ 38 4.1.1 锚网索耦合支护的主要作用 ............................................................. 38 4.1.2 锚网索耦合支护作用 ......................................................................... 39 4.2 预应力锚杆支护参数的影响分析 ................................................................ 44 4.2.1 数值模拟模型 ...................................................................................... 44 4.2.2 预应力锚杆间距对应力场的影响分析 .............................................. 47 4.2.3 预应力锚杆的布置角度对围岩应力场的影响 .................................. 48 4.3 预应力锚杆锚索联合支护对巷道应力场的影响分析 ............................ 49 4.4 本章小结 ....................................................................................................... 53 第第 5 章章 高应力软岩回采巷道蠕变控制研究高应力软岩回采巷道蠕变控制研究 ........................................................ 54 5.1 蠕变控制总体要求 ........................................................................................ 54 5.2 软岩巷道围岩流变特性的分析 .................................................................... 55 5.2.1 围岩应力的重新分布及时间效应 ...................................................... 55 5.2.2 巷道围岩应力与变形的流变分析 ...................................................... 57 5.3 巷道锚网索与围岩耦合支护巷道内的流变模型 ........................................ 61 5.3.1 锚固体的流变模型与本构方程 .......................................................... 61 5.3.2 锚网索与围岩支护流变本构方程 ...................................................... 69 5.4 高应力软岩巷道让压支护的技术研究 ........................................................ 70 5.4.1 软岩工程让压支护现状 ...................................................................... 70 5.4.2 让压支护对软岩巷道围岩的控制作用 .............................................. 71 5.5 锚杆与锚索联合支护（二次支护）巷道流变分析 .................................... 73 5.5.1 锚杆（索）预紧力对高应力软岩回采巷道变形影响分析 .............. 73 5.5.2 锚杆（索）支护强度对高应力软岩回采巷道变形影响分析 .......... 77 5.6 本章小结 ........................................................................................................ 80 第第 6 章章 高应力软岩回采巷道支护参数优化设计高应力软岩回采巷道支护参数优化设计 ................................................ 81 6.1 锚杆支护参数优化模型 .....................................................