基于微细观力学的砂质泥岩蠕变破坏机理研究.pdf

硕士学位论文 基于微细观力学的砂质泥岩蠕变破坏机理研究 Study on the Creep Failure Mechanism of Sandy Mudstone Based on Micro-Mesoscopic Mechanics 国家重点国家重点研发研发计划项目计划项目2017YFC0603001资助资助 国家自然科学基金重点项目国家自然科学基金重点项目51734009资助资助 作 者陈伟强 导 师靖洪文 教授 中国矿业大学 二〇一九年五月 万方数据 学位论文使用授权声明学位论文使用授权声明 本人完全了解中国矿业大学有关保留、使用学位论文的规定，同意本人所撰写的 学位论文的使用授权按照学校的管理规定处理 作为申请学位的条件之一，学位论文著作权拥有者须授权所在学校拥有学位论文 的部分使用权，即①学校档案馆和图书馆有权保留学位论文的纸质版和电子版，可 以使用影印、缩印或扫描等复制手段保存和汇编学位论文；②为教学和科研目的，学 校档案馆和图书馆可以将公开的学位论文作为资料在档案馆、图书馆等场所或在校园 网上供校内师生阅读、浏览。另外，根据有关法规，同意中国国家图书馆保存研究生 学位论文。 （保密的学位论文在解密后适用本授权书） 。 作者签名 导师签名 年 月 日 年 月 日 万方数据 中图分类号 TU45 学校代码 10290 UDC 624 密 级 公开 中国矿业大学 硕士学位论文 基于微细观力学的砂质泥岩蠕变破坏机理研究 Study on the Creep Failure Mechanism of Sandy Mudstone Based on Micro-Mesoscopic Mechanics 国家重点国家重点研发研发计划项目计划项目2017YFC0603001资助资助 国家自然科学基金重点项目国家自然科学基金重点项目51734009资助资助 作 者 陈伟强 导 师 靖洪文 教授 申请学位 工学硕士学位 培养单位 力学与土木工程学院 学科专业 岩土工程 研究方向 岩石力学 答辩委员会主席 蒋斌松 评 阅 人 杨圣奇、翟明华 二○一九年五月 万方数据 致谢致谢 本论文是在恩师靖洪文教授悉心指导下完成的，论文从选题、制定研究方案直至 最后完稿都凝聚着恩师的远见卓识。恩师以其深厚学识积淀和对学科前沿热点的精准 把握为学生指明了研究方向。没有恩师的支持、鼓励、点拨及鞭策，论文不可能顺利 完成。在此，特向恩师致以衷心的感谢和最诚挚的敬意 感谢蒋斌松教授、李元海教授、韩立军教授、杨圣奇教授、蔚立元教授、王迎超 教授、孟庆彬副教授、张强副教授、陈坤福副教授、许国安副教授在论文选题中给予 的诸多指导和帮助。 感谢课题组苏海健副教授、孟波老师、尹乾老师在试验结果分析及论文书写过程 中的指导和帮助。 感谢课题组高远博士、丁书学博士、朱文心博士、朱栋博士、杜明瑞博士、韩观 胜博士、史新帅博士、赵振龙博士、杨利军硕士、张力硕士、吴应杰硕士、李林林硕 士、胡涛硕士、卜若迪硕士、顾晓伟硕士、符光平硕士、李峦硕士、周泽敷硕士以及 同窗王珂硕士、胡成果硕士、贺立新硕士在试验中给予的大力帮助。感谢 418 办公室 闵明硕士、郭强硕士、李诚硕士、孟凡树硕士在学习上提供的帮助。 感谢我的舍友徐晓鼎硕士、 胡翔骞硕士、 史伟男硕士以及三年来朝夕相处的同学， 谢谢他们在学习和生活中给予的帮助。 感谢父母对我的养育之恩和对我学业的关心和支持，祝他们健康长寿。 感谢我的妻子一直以来对我的支持和鼓励。 感谢论文所引用文献的作者。 感谢各位专家、教授在百忙之中对论文的审阅、答辩与批评指导。 万方数据 I 摘摘 要要 岩石蠕变本质上是其内部微细观结构（各种尺度缺陷和造岩矿物）在恒定荷载下 随时间发生损伤、劣化、重组、细化、滑移等微细观作用的过程。目前，针对岩石蠕 变的研究主要集中在岩石的宏观蠕变特性和规律方面，对岩石蠕变机理的微细观研究 还相对不足。随着岩土工程问题日趋复杂，仅靠对岩石蠕变宏观表象规律性方面的研 究已无法满足岩土工程发展的需求，亟需加深对岩石蠕变微细观内在机理的研究。为 此，本文以国投新集口孜东矿千米深井煤矿为背景，结合国家自然科学基金重点项目 “深部开采与巷道围岩稳定控制信息化基础理论研究”（51734009）和国家重点研发计 划项目（2017YFC0603001）子课题“千米深井强采动巷道围岩劣化与强度衰减规律”， 以该矿典型砂质泥岩为研究对象，基于微细观力学开展砂质泥岩蠕变破坏机理研究， 主要研究内容及结论如下 1 首先对取自口孜东矿 111302 工作面高抽巷的砂质泥岩试样，进行矿物组分和 孔隙结构的微细观表征分析， 并与该矿典型砂岩、 煤试样的微细观结构特征进行对比， 对于该矿所取的三种典型岩样，微米级别孔隙度大小呈现的关系为煤＞砂质泥岩＞ 砂岩。砂岩试样在毫米级别的孔隙最多，意味着渗透性能良好，整体结构由大量砂粒 胶结而成；煤试样在微米级别的孔隙最多，颗粒之间胶结较弱；砂质泥岩试样在微米 级别的孔隙度，及胶结情况介于煤和砂岩试样之间，含有大量的黏土矿物。说明微细 观结构差异是导致口孜东矿巷道不同岩性围岩变形特性和机理不同的重要原因。 2 基于声发射和数字图像量测技术进行了砂质泥岩室内微细观蠕变试验。结果 表明砂质泥岩蠕变过程中声发射曲线与蠕变曲线具有相同的变化趋势，可分为减速、 等速、加速三个阶段。声发射事件三维定位结果表明，恒定荷载的时效作用是使砂质 泥岩的微细观损伤趋于均匀化、扩散化。蠕变作用下砂质泥岩表面细观变形场在蠕变 速率降至 0 时将呈现均匀对称的等值线分层；处于非稳定蠕变状态时则无法呈现，揭 示了砂质泥岩蠕变因细观变形场不均匀不对称而产生滑移破坏的变形机理。将传统的 整数阶元件模型替换为分数阶元件模型，基于函数阶微积分理论建立了砂质泥岩函数 阶蠕变本构模型，通过计算模型阶数随蠕变时间和应力水平的演变，研究了砂质泥岩 试样在蠕变作用下的黏-弹性转化效应。 3 采用扫描电子显微镜SEM技术、 三维扫描技术对砂质泥岩蠕变破裂面进行了 微细观形貌分析以及微观形貌的分形盒维数计算，阐明了砂质泥岩蠕变破裂面微细观 粗糙度与砂质泥岩细观剪胀效应的关系；获得了砂质泥岩多级蠕变过程中的瞬时应变 量随应力水平升高而降低，随砂质泥岩内部可压缩相（黏土矿物）的压密而呈现硬化 效应的变化规律；而砂质泥岩蠕变破裂面在微细观层面上比瞬时压缩破裂面更松散， 万方数据 II 更粗糙，进一步导致了砂质泥岩蠕变时的细观剪胀角比瞬时压缩时更大，易呈现明显 的细观剪胀效应。 4 基于 Potyondy 提出的考虑时效损伤的颗粒离散元应力腐蚀模型PSC， 进行了 PFC 接触蠕变模型的二次开发和砂质泥岩蠕变的数值模拟；利用广州“天河二号”超级 计算机系统的大规模并行计算能力，进行分子动力学模拟。模拟在微细观层面上数值 再现了砂质泥岩蠕变的微细观损伤演化过程及机理。砂质泥岩蠕变过程中的细观颗粒 体系全能量曲线揭示了外部恒定荷载做功导致的能量输入与细观损伤能量耗散的相 互转化，相互促进的关系；原子级别的数值仿真再现了石英晶体微观接触的瞬时弹性 行为和时效应力腐蚀行为。揭示了石英晶体微观接触应力腐蚀及应力松弛现象的机理 为石英晶体微观接触处产生的原子高势能和高应力使原子从晶体结构中加速“逃逸” 的概率大大增加，时间效应又增加了原子最终逃逸的概率，原子逃逸造成了石英晶体 结构的破坏，这种破坏进一步导致了接触力不断被消解，产生应力松弛现象。同时分 子动力学模拟也证明了松弛是石英晶体结构应变能（势能）耗散的过程，与蠕变有所 不同。 该论文有图 93 幅，表 7 个，参考文献 133 篇。 关键词关键词砂质泥岩；蠕变；离散元；应力腐蚀模型；分子动力学 万方数据 III Abstract Essentially, the creep behavior of rock is the result of constant damage, degradation, refinement and sliding of its microscopic component under the constant loading. Currently, most of researches focus on the macroscopic deation characteristics and regular patterns of rock in the creep action. And the studies on the micro-mesoscopic mechanisms of rock creep behavior are far from enough. With the problems of geotechnical engineering being increasingly complex, it will be of great significance to deepen the understandings of the inherent mechanisms of rock creep behavior. In this study, the sandy mudstone samples from KouZiDong Coal Mine were taken as the main research object. Mechanisms of sandy mudstone creep behavior was investigated based on micro-mesoscopic mechanics. The main research contents and conclusions are listed as below 1 The micro-mesoscopic structures of typical sandy mudstone, sandstone and coal from KouZiDong Coal Mine were analysed in order to reveal the mechanisms of different rocks’ deation behavior. The porosity of 3 kinds of rocks showed that coal sandy mudstone sandstone. And the cementingbonding status showed that sandstone sandy mudstone coal. The sandy mudstone was mainly composed of clay minerals. The micro-mesoscopic structure of sandy mudstone plays a key role in its deation behavior. 2 Micro-mesoscopic rheological tests were conducted on sandy mudstone samples based on AE and DICM technologies. The test results showed that 1 The AE versus time curve of sandy mudstone samples in the creep action was consistent with the axial rheological strain versus time curve of sandy mudstone samples. Three stages were identified decelerated stage, steady stage and accelerated tertiary stage. 2 The AE spatial distribution of sandy mudstone samples in the creep action revealed that the ageing action of constant load was to make the damage in sandy mudstone more homogeneous and more dispersed. 3 The surface deation field of sandy mudstone samples showed symmetrical isoline when the sandy mudstone sample was in the stable creep stage. But this could not be observed when the sandy mudstone sample was in the unstable creep stage and consequently, shear sliding failure occurred. 4 Based on the of variable-order fractional calculus, the creep characteristics of sandy mudstone sample was analysed. 3 SEM and 3D Scanning technologies were adopted to study the creep-induced fracture surfaces’ meso-micromorphology of sandy mudstone samples and the box fractal dimensions of micromorphology was calculated. The relation between mesoscopic 万方数据 IV asperities and micro-mesoscopic shear dilation effect was investigated. The hardening effect observed in the step-loading uniaxial creep test was well explained as the result of internal clay minerals’ compaction based on the SEM images. The fracture surfaces of sandy mudstone samples from creep tests were rougher and more dispersed than that from uniaxial compression tests at the micro-mesoscopic level. Hence, micro-mesoscopic shear dilation effect of sandy mudstone fracture surfaces was more obvious. This is an important reason for creep-induced larger deation. 4 Based on the time-dependent Parallel-Bonded Stress Corrosion Model PSC presented by Potyondy, the secondary development of PFC creep contact model was accomplished and numerical simulations on sandy mudstone creep behavior was conducted in this study. Based on the large-scale parallel computing capability of “Tianhe-2” supercomputer system, relative molecular dynamics simulation was conducted. The above numerical simulations reproduced the micro-mesocopic damage evolution and failure mechanisms of sandy mudstone in the creep action. The energy curves of the particle system in PFC revealed that the work done by applied constant force the energy into the sandy mudstone samples and some energy were dissipated by the cracking processes and damage evolution of sandy mudstone samples. The and dissipation processes were in the relation of mutual promotion and mutual transation. The atomic level simulations numerically reproduced the phenomenon of instantaneous elasticity and stress corrosion in the interfaces of quartz contact. It revealed the mechanisms of stress corrosion and stress relaxation of quartz contact interfaces, that is, the high potential energy and contact stress in the quartz contact interfaces significantly increase the atoms’ abilities to run out of the quartz crystal. And time increases the probability of ultimate escape. The quartz crystal is destroyed when the atoms run out of it. Hence, the initial contact pressure is decreased constantly. The stress corrosion and relaxation occurr. At the same time, this numerical simulation proved that the mechanism of stress relaxation is the dissipation of strain energy potential energy of quartz crystal, which is somewhat different from that of creep. There are 93 pictures, 7 tables and 133 references. Keywords sandy mudstone; creep; discrete element ; parallel-bonded stress corrosion model; molecular dynamics simulation 万方数据 V 目目 录录 摘摘 要要 ......................................................................................................................................... I 目目 录录 ....................................................................................................................................... V 图清单图清单 ...................................................................................................................................... IX 表清单表清单 .................................................................................................................................... XV 变量注释表变量注释表 ........................................................................................................................... XVI 1 绪论绪论 ........................................................................................................................................ 1 1.1 问题提出及研究意义 ......................................................................................................... 1 1.2 国内外研究现状 ................................................................................................................. 1 1.3 主要研究内容及技术路线 ................................................................................................. 8 2 砂质泥岩砂质泥岩蠕变损伤演化过程的微细观试验研究蠕变损伤演化过程的微细观试验研究 .............................................................. 10 2.1 试样制备及其微细观表征分析 ....................................................................................... 10 2.2 基于声发射与数字照相量测技术的细观试验系统 ....................................................... 14 2.3 蠕变作用下砂质泥岩长期强度与声发射时空演化特征 ............................................... 17 2.4 蠕变作用下砂质泥岩宏细观变形场演化特征 ............................................................... 23 2.5 基于函数阶微积分的砂质泥岩蠕变特性分析 ............................................................... 28 2.6 本章小结 ........................................................................................................................... 33 3 基于粗糙度与分形理论的基于粗糙度与分形理论的砂质泥砂质泥岩岩蠕变蠕变破裂破裂面微细观剪胀机理研究面微细观剪胀机理研究 ......................... 35 3.1 砂质泥岩蠕变破裂面微细观表征技术 ........................................................................... 36 3.2 砂质泥岩蠕变破裂面微观形貌及分形特征 ................................................................... 37 3.3 砂质泥岩蠕变破裂面细观粗糙度分析 ........................................................................... 44 3.4 砂质泥岩蠕变破裂面细观粗糙度与细观剪胀效应关系研究 ....................................... 48 3.5 本章小结 ........................................................................................................................... 50 4 基于离散单元法和分子动力学模拟的基于离散单元法和分子动力学模拟的砂质泥岩砂质泥岩蠕变微细观损伤破坏机理研究蠕变微细观损伤破坏机理研究 ......... 52 4.1 单轴压缩条件下砂质泥岩细观损伤破坏机理研究 ....................................................... 53 4.2 基于应力腐蚀模型的砂质泥岩蠕变细观损伤破坏机理研究 ....................................... 59 4.3 基于分子动力学的石英晶体应力腐蚀与松弛微观机理研究 ....................................... 74 4.4 本章小结 ........................................................................................................................... 84 5 结论与展望结论与展望 .......................................................................................................................... 86 万方数据 VI 5.1 主要结论 ........................................................................................................................... 86 5.2 展望 ................................................................................................................................... 87 参考文献参考文献 .................................................................................................................................. 89 作者简历作者简历 .................................................................................................................................. 97 学位论文原创性声明学位论文原创性声明 .............................................................................................................. 99 学位论文数据集学位论文数据集 .................................................................................................................... 100 万方数据 VII Contents Abstract .................................................................................................................................. III Contents ................................................................................................................................. VII List of Figures ......................................................................................................................... IX List of Tables ......................................................................................................................... XV List of Variables ................................................................................................................... XVI 1 Introduction ........................................................................................................................... 1 1.1 Problem Posing and Research Significance ......................................................................... 1 1.2 Present Research Status at Home and Abroad ..................................................................... 1 1.3 Main Research Contents and Technical Route ..................................................................... 8 2 Micro-Mesoscopic Experimental Study on Creep Evolution Process of Sandy Mudstone ................................................................................................................................. 10 2.1 Test Specimens Preparation and Its Micro-Mesoscopic Characterization ......................... 10 2.2 Mesoscopic Test System Based on Acoustic Emission and Digital Image Correlation ..................................................................................................................................... 14 2.3 The Long-Term Strength and Acoustic Emission Spatio-Temporal Evolution Characteristics of Sandy Mudstone in the Creep Action .......................................................... 17 2.4 The Macro-Mesoscopic Deation Field Evolution Characteristics of Sandy Mudstone in the Creep Action .................................................................................................. 23 2.5 Analysis on Creeping Properties of Sandy Mudstone Based on Variable-Order Fractional Calculus .