大断面煤巷围岩稳定性控制及动态评价体系研究.pdf

太原理工大学 博士学位论文 大断面煤巷围岩稳定性控制及动态评价体系研究 姓名张召千 申请学位级别博士 专业岩土工程 指导教师康立勋 20090401 太原理工大学博士研究生学位论文 I 大断面煤巷围岩稳定性控制及动态评价体系研究 摘 要 煤巷围岩大多属于层状或块状结构，其本身强度较低，且节理裂隙发 育，完整性较差；同时受复杂外部工程环境的影响，煤巷围岩控制和支护 越来越成为煤矿生产与安全的重要难题。究其原因，主要存在的问题是① 对煤巷围岩地质力学特性和工程环境条件缺乏准确的掌握和科学的评价； ②对煤巷围岩的变形失稳机理的认识不够清楚；③缺乏针对煤巷围岩力学 特性的围岩控制和锚固理论；④未能对煤巷围岩的稳定性做出科学有效的 评价；⑤煤巷围岩稳定性评价与支护设计不能紧密结合，不能用于指导围 岩控制和支护设计。目前人们对特定条件下煤巷围岩稳定性缺乏科学定量 的判断手法，缺乏对不同巷道围岩稳定性进行科学评价的理论体系，从而 影响煤巷围岩控制和支护效果。因此，深入探讨煤巷围岩稳定性控制及锚 固理论，运用岩层控制学及地质力学理论系统研究大断面煤巷围岩的地质 力学特性和所处工程环境条件的影响，准确掌握围岩结构及其对围岩稳定 性的影响，探索出一条以支护设计为中心的适用于大断面煤巷的围岩稳定 性评价体系成为急待解决的技术课题。 煤巷围岩稳定性控制与评价的目的是科学准确的反映巷道围岩结构的 复杂性，为煤巷围岩控制和支护设计提供可靠依据。总结国内外对煤巷围 岩的各种评价方法，发现存在反映的全面性不足，侧重点和选用指标以及 分级方法也欠准确。目前国内外对煤巷围岩稳定性控制和评价研究主要表 现为如下特点 1对煤巷围岩地质力学特性和工程环境条件的研究不够全面和准确， 对煤巷围岩的变形失稳机理的认识不够清楚；缺乏针对煤巷围岩力学特征 的稳定性控制及锚固理论。 2围岩稳定性分类现在虽然由单因素定性分级向多因素定性和多因 太原理工大学博士研究生学位论文 II 素定量动态模式发展，但影响围岩质量的多种因素具有明显的不确定性、 复杂性和模糊性特征，用少数几个固定评价指标和简单的数学表达式难以 准确、全面地概括其真实情况，围岩质量的完全定量化分级只能具有数学 意义。 3各类围岩质量的评价方法都是从不同侧面选择几个固定的参评因 素，按一定标准进行简单的线性运算，从而得出围岩质量的单一评分，并 据此进行围岩稳定性分类。这些方法虽然简单方便，但无法反映复杂多变 的地质情况，只能反映围岩稳定性的某一方面特征。由于影响围岩稳定性 的因素常具有多层次性、模糊性、不确定性等复杂特点，对于不同地质背 景和具体工程，其影响因素及权值都不是固定的，既有共同性，又有特殊 性。 4围岩稳定性的分类主要是针对矿区地质条件下巷道具有的共性进 行分析，而在同一矿区甚至同一巷道，巷道围岩状况具有很大的差异，受 地质构造和相邻工程环境影响的不同形成局部的特殊性。在同一矿区巷道 围岩稳定性各不相同，进行评价时应充分考虑地质构造和工程环境的影响。 因此，巷道围岩稳定性评价应当采用静态和动态等多种评价方法从不 同侧面进行围岩稳定性的动态评价。在同一矿区进行巷道稳定性评价时应 充分考虑个体巷道所处不同的地质构造和工程环境的影响。 本文以上述观点为基础，以山西亚美大宁能源有限公司大断面煤巷和 矿区地质构造为研究对象，采用理论分析、现场实测、数值模拟计算和工 业性试验等方法，对煤巷围岩稳定性控制理论、地质力学评价与支护设计、 扰动因素影响加权与修正、数值模拟分析与验证优化等几个方面做了探索 性研究；形成了煤巷围岩稳定性控制和动态评价体系。主要研究成果如下 1以煤巷围岩地质力学特性为基础，研究煤巷围岩应力分布特征和支 护对煤巷围岩稳定性的影响机理，探讨煤巷围岩的变形破坏规律。 2运用弹塑性理论分析煤巷围岩的稳定性状态，揭示煤巷围岩失稳破 坏机理，依据裂隙体及破碎体的煤体力学特征，运用厚板（体）理论进行 太原理工大学博士研究生学位论文 III 煤体两帮锚固体厚度、锚杆几何和力学参数设计。 3研究煤巷在不同围岩稳定性平衡状态下的控制和锚固原理；提出对 围岩稳定性状态较好的围岩采用状态控制原理，对稳定性状态差的大变形围 岩采用变形控制原理；对围岩整体强度低，围岩应力状态呈静水压力状态的 采用整体锚固结构原理。 4以煤巷围岩控制和支护设计为中心，运用岩层控制学和地质力学理 论，采用地质力学评价与支护设计、扰动因素影响加权与修正、数值模拟 分析与验证优化，形成了三位一体的巷道围岩稳定性动态评价体系。 5运用现场取芯和实验室力学测试方法，研究分析 15m 范围内围岩各 岩层的地质力学特性指标。进行煤巷围岩稳定性初步评价和支护方案设计。 建立地质力学特性分析稳定性评价支护设计为一体的地质力学评价方 法。 6确定了外部扰动因素（地质构造、相邻工程、采动压力）对围岩稳 定性影响的重要性；针对煤巷所处工程环境特点，分析地质构造、相邻工 程、采动压力外部扰动因素对煤巷围岩稳定性的影响范围及影响等级，确 定扰动因素权值，进行影响程度评价和对初步支护方案进行修正，形成了 独特的扰动因素加权评价方法。 7运用数值模拟方法分析煤巷在无支护状态下和在支护方案条件下围 岩的应力和变形分布规律。验证煤巷围岩的稳定状态，优化支护设计方案 和支护参数。 总之，本文通过系统研究，建立了大断面煤巷围岩稳定性控制及动态 评价体系，解决了大断面煤巷围岩稳定性控制和支护存在的实际问题，为 今后煤巷围岩控制、稳定性评价和支护设计提供科学依据。 关键词大断面煤巷，围岩稳定性，控制原理，动态评价体系，支护 设计 太原理工大学博士研究生学位论文 IV RESEARCH ON THE SURROUNDING ROCK STABILITY CONTROL AND DYNAMIC APPRAISEMENT SYSTEM OF LARGE SECTION ROADWAY ABSTRACT Most surrounding rocks in coal roadway belong to layered or massive structure with low intensity, joint fissures, and poor integrity; influenced by many project environmental factors simultaneously, it becomes a difficult problem more and more that how to control and support the surrounding rock for production and safety in coal mine. Tracing its reasons, the main problems include ① it lacks accurate mastering and scientific appraisement about geological mechanical properties and project environmental condition; ② there is no clear recognition to the deation destabilizing mechanism of roadway surrounding rock;③ there is no enough stability control and anchorage theory aimed at the mechanical properties of roadway surrounding rock; ④ accurate and scientific appraisement on the stability of roadway surrounding rock cannot be made; ⑤ the surrounding rock stability appraisement cannot be combined with support design closely and cannot guide the surrounding rock control and support. There is no scientific quantitative judgment technique direct to the stability of roadway surrounding rock under special conditions; it lacks scientific theory system for appraising on the stability of different roadway surrounding rocks, which all influence the stability control and support effect of roadway surrounding rock. Therefore, it is a technique subject pressing for solution to further discuss on stability control and anchorage theory of roadway surrounding rocks, systematically study the influence of geological mechanical properties of surrounding rock in large section roadway and project environmental condition utilizing strata control science and geological mechanical theory, accurately master the structure of surrounding rock and its influence on surrounding rock 太原理工大学博士研究生学位论文 V stability, and taking support design as the central explore a surrounding rock stability appraisement system which is suitable for large section roadway. The surrounding rock stability control and appraisement in coal roadway aims to reflect the complexity of surrounding rock structure scientifically and accurately and to provide a reliable basis for the roadway surrounding rock control and support design. Summarized all kinds of appraisement s at home and aboard, we can see that those s had insufficient integrity, the emphasis points, the selected indicators and grading s were diffident. At present the studies on surrounding rock stability control and appraisement in coal roadway at home and aboard mainly have the following characteristics 1 The study on geological mechanical properties and project environmental condition of surrounding rock in coal roadway is not very comprehensive and accurate. There is no clear recognition to deation destabilizing mechanism of roadway surrounding rock. There is no enough stability control and anchorage theory aimed at the mechanical properties of roadway surrounding rock. 2 The classification of surrounding rock stability is developing from the mode of single factor and qualitative graduation to the dynamic mode of multi-factors and quantitative graduation. However, the factors influencing surrounding rock quality have obvious characteristics of uncertainty, complexity and fuzziness. It is difficult to generalize the practical situations accurately and comprehensively by minority fixed appraisement indicators and simple mathematical expressions, and the complete quantitative graduation of surrounding rock quality only has mathematical significance. 3 All kinds of surrounding rock quality appraisement s select several fixed participating factors from different sides, and carry on simple linear operation according to certain standards, then obtain single scores of surrounding rock quality, and then based on these scores make classification about the stability of surrounding rock. Although these s are simple and convenient, they cannot reflect the complicated and diversified geological 太原理工大学博士研究生学位论文 VI situation, but only reflect one aspect characteristic of surrounding rock stability. The factors influencing the surrounding rock stability usually have complex characteristics of multi-levels, fuzziness, uncertainty, etc. Regarding the different geological backgrounds and the concrete project, their influencing factors and weights are not fixed, which both have the intercommunity and the particularity. 4 The classification of rock stability is founded on analysis mainly on the intercommunity of geological condition in mining areas. However, in same mining area even in same roadway, the rock condition has great difference and each s partial particularity as result of the different influence of geologic structure and neighboring project environment. The rock stability is different in same mining roadway, so we should consider the influence of geologic structure and project environment completely while carrying on appraisement. Therefore, the stability appraisement of roadway surrounding rock should adopt both static and dynamic appraisement s to dynamically appraise from different sides. In same mining area we should consider the influence of geologic structure and project environment where the individual roadway locates while carrying on appraisement. Based on the above viewpoints, taken large section coal roadway of Shanxi Yamei Daning energy Limited company and geological structure as the study objects, this paper has adopted theoretical analysis, field measurement, numerical simulation calculation, industrial experiment and other s to make an exploratory research on the surrounding rock stability control theory in coal roadway, geological mechanical appraisement and support design, the influencing weight and revision of the disturbance factors, numerical simulation and verified optimization, and ed the surrounding rock stability control and dynamic appraisement system. The main research achievements as follows 1 Based on geological mechanical properties in coal roadway surrounding rock, the paper has studied the characteristic of stress distribution and the mechanism that support influence roadway surrounding rock stability, and 太原理工大学博士研究生学位论文 VII discussed on the rule of deation and destruction of coal roadway surrounding rock. 2 The research has analyzed the stability condition of coal roadway surrounding rock utilizing elastic-plastic theory, exposed the destabilization and destruction mechanism of surrounding rock, and also according to coal seam’s mechanical properties of cracked body and coal body studied how to design the anchorage wall’s thickness, bolts’ geometric and mechanical parameters of the broken sides using thick plate theory. 3 The paper has researched the principle of control and anchorage under the different equilibrium states of surrounding rock stability; and suggested adopting the principle of state control for surrounding rock with good stable condition, the principle of deation control for surrounding rock with bad stable condition, and the principle of whole anchorage structure for surrounding rock with low intensity and hydrostatic pressure state. 4 Taken stability control of roadway surrounding rock and support design as the central, utilizing strata control science and geological mechanical theory, the paper has ed a trinity dynamic appraisement system of roadway surrounding rock stability based on geological mechanical appraisement and support design, the influencing weight and revision of the disturbance factors, numerical simulation and verified optimization. 5 Through taking the core on spot and testing it in the laboratory, the paper has made experimental analysis on each layer’s geological mechanical properties in 15m scope. Also it has made preliminary appraisal on surrounding rock stability and design of support scheme, and constructed the appraisement based on the trinity of geological mechanical properties of surrounding rock, stability appraisement and support design. 6 The paper has confirmed the importance that the exterior disturbance factors geological structure, neighboring project had influence on surrounding rock stability; In view of the characteristic of project environment where the coal roadway locates, the paper has analyzed the influencing scope 太原理工大学博士研究生学位论文 VIII and graduation of each exterior disturbance factor including geologic structure, neighboring project environment and mining pressure to the stability of roadway surrounding rock, fixed the weight of disturbance factors, appraised the influence and revised the supporting scheme of surrounding rock stability, and ed a unique appraisement system based on the disturbance factor weight. 7 Utilizing numerical simulation analysis, the paper has researched the stress and deation distribution rule and the characteristic of abscission layer under supporting and non-supporting roadway surrounding rock. And through the analysis on the stability state of surrounding rock, the paper identified and optimized the supporting scheme. In a word, this paper constructed the surrounding rock stability control and dynamic appraisement system of large section roadway through systematic research, which has solved the actual problems existing in the surrounding rock stability control and support of large section roadway and provided a scientific basis for the future control and support of surrounding rock in coal roadway. KEYWORDS large section roadway; surrounding rock stability; control principle; dynamic appraisement system; support design 太原理工大学博士研究生学位论文 1 第一章 绪 论 1.1 选题的目的和意义 我国煤炭资源丰富，在相当长的时间内，一次性能源结构中煤炭所占的比重一直在 67％以上，始终处于主体地位；煤炭工业在我国国民经济中占有举足轻重的地位。高效 合理地开发煤炭资源对整个国民经济的发展有着重要作用。 据预测， 2020 年全国煤炭需 求量约占一次性能源消费的 60％ [1-3]。因此，在我国合理开发利用煤炭资源，减少事故 发生，建设安全高效现代化矿井，对于维护社会稳定和促进国民经济持续发展有着特殊 重要意义。 由于地质条件的成因不同，煤层的赋存条件各异。煤层的结构、完整性、力学指标 差异很大，煤层顶底板岩性及倾角更是千变万化。由此导致煤巷围岩赋存条件具有复杂 性和多变性，造成围岩控制和支护困难，直接影响矿井的安全生产。如何对所处不同环 境条件下的煤巷进行科学的围岩稳定性评价和控制， 实现安全高效生产是煤炭企业一直 关心的重要问题 [2-8]。 近年来，煤巷围岩稳定性评价和控制技术在我国越来越引起大家的广泛重视，其原 因有两个 （1）矿井开采由浅部向深部扩展，地层压力增大，围岩控制困难。随着我国 煤炭资源的持续开采，矿区浅部煤层储量越来越少。特别是近年来快速发展的高产高效 技术，已经使大部分矿区浅部煤层的服务年限接近枯竭，煤炭开采从浅部向深部扩展， 如淮南等地开采深度已达千米，随之带来的是地层压力的明显增大，地质构造、瓦斯、 水等自然条件对巷道围岩稳定性的影响越来越大， 巷道围岩稳定性变差， 围岩控制困难， 支护效果不佳，巷道变形破坏严重。 （2）煤巷断面越来越大，围岩控制和支护越来越难。 过去巷道断面大部分都在 10 ㎡以下，巷道宽度在 3 米以下；随着煤矿采用综采工艺和 机械化程度的提高，为满足井下大型设备的运输和安装，原来的小断面巷道已不能满足 生产的要求，巷道断面变的越来越大；如晋城矿务局寺河矿、山西亚美大宁能源有限公 司巷道断面都在 19 ㎡以上，巷道宽度在 5.5 米以上，交岔点宽度达 9.5 米，由此带来 巷道对围岩稳定性的影响范围增大，影响程度加剧，导致围岩控制困难。 （3）煤巷围岩 强度低，变形大。且多在煤层中布置，巷道顶、底板围岩多为炭质泥岩、泥岩、砂质泥 岩、粉砂岩和砂岩，岩层层理、裂隙发育，自身强度低，完整性差，围岩的力学特性较 太原理工大学博士研究生学位论文 2 差，造成支护难度加大。同时巷道呈群体布置，相互干扰严重，这也是造成围岩稳定性 差，支护困难的一个原因。如晋城矿务局寺河矿、山西亚美大宁能源有限公司煤巷每组 平行布置 3～7 条。 显然， 要保证煤矿安全高效和可持续发展就必须解决大断面煤巷围岩稳定性评价和 控制这个技术问题。 长期以来，人们的研究已经取得了很大成就 [27]，出现了工程类比法，理论计算法， 专家系统法，数值模拟法，软件分类法等围岩稳定性控制原理和分类方法。但是，对大 断面煤巷在复杂地质条件下的围岩稳定性控制和评价仍研究不足，成果也较少，缺乏对 工程外部环境条件的影响评价。大断面煤巷围岩稳定性控制和动态评价体系研究主要涉 及 （1）煤巷围岩应力分布特征及变形破坏规律； （2）煤巷围岩失稳破坏机理，煤巷围 岩稳定性控制及加固原理。 （3）煤巷围岩地质力学特征分析及稳定性评价； （4）地质构 造及相邻工程环境对围岩稳定性的影响及评价； （4）建立一套用于指导支护设计的大断 面煤巷围岩稳定性动态评价体系。 对煤巷围岩应力分布规律、屈服变形特征、失稳破坏机理、围岩稳定性控制和锚固 原理等方面的研究主要是以煤巷围岩的地质力学特征为基础， 研究围岩应力分布规律和 支护对稳定性的影响机理，探讨围岩的变形破坏特征。运用弹塑性理论分析围岩的稳定 性状态，揭示围岩失稳破坏机理，根据裂隙体及破碎体的煤体力学特征，利用厚板（体） 理论进行煤巷两侧锚固体厚度、锚杆几何和力学参数设计。研究煤巷在不同围岩稳定性 平衡状态下采用的控制理论和锚固原理； 提出对稳定性状态较好的围岩采用状态控制原 则，对稳定性状态差的大变形围岩采用变形控制原则；对围岩整体强度低，围岩应力状 态呈静水压力状态的采用整体锚固结构原理。 对大断面煤巷围岩地质力学特征及稳定性评价方面的研究目前主要在围岩各岩层 力学参数（抗压强度、抗拉强度、抗剪强度、弹性模量、泊松比、内聚力、内摩擦角、 容重等）的测定，岩层的完整性（层理、节理、裂隙的发育情况）分析和支护关键层的 确定上；而对与支护设计密切相连的整体稳定性分析、加固层厚度与支护参数的关系， 煤巷顶板围岩与两帮煤体的差异性， 无支护关键层时锚索参数的确定等核心问题研究的 很少。 地质构造和相邻工程环境对围岩稳定性的影响及评价研究主要形成了以太沙基理 论为基础的上覆岩层重量传递的计算方法 （其基本理论是施加到巷道围岩的地应力为上 覆岩层的重量 σ＝γH） 、 大地构造应力场理论和现场地应力实测方法； 但对地质构造对 太原理工大学博士研究生学位论文 3 围岩稳定性的影响目前还只停留在宏观定性的水平上，而对地质构造的影响范围、影响 等级、影响特征等方面的研究还较少；相邻工程环境对围岩稳定性的影响主要在相邻巷 道、采煤工作面上（分析以煤柱宽度、采高比为指标） ；而且是以定性为主，缺乏科学 的定量分析评价。 大断面煤巷支护效果不佳的主要原因是缺乏科学的围岩稳定性控制理论， 不能对煤 巷围岩的稳定性做出科学的评价，不能将煤巷围岩稳定性控制理论、评价体系与支护设 计紧密地联系在一起，前者不能用于指导支护设计，从而导致了巷道支护的不确定性。 其主要问题表现在①支护设计采用经验类比法的较多；②同一个矿区的巷道基本采用 同一种支护方案；③同一条巷道基本采用同一种支护方案；④锚杆支护材料、布置形式 和支护参数大体相同。究其原因，主要是对特定条件下煤巷围岩稳定性控制缺乏科学的 理论体系，缺乏以支护设计为中心的煤巷围岩稳定性科学评价体系。 巷道围岩稳定性评价在于全面反映巷道所处工程地质力学环境，地应力状态，围岩 的地质力学性质、裂隙弱面结构及完整性特征，为支护参数设计提供可靠依据，对围岩 稳定性做出科学的评价，确定合理的支护方案与支护参数。 综上所述， 现有的大断面煤巷围岩稳定性控制与评价理论和技术不能完全反映其真 实状态。 国内外关于大断面煤巷围岩