基于颗粒离散元的砂岩渗流时效破裂规律及应用.pdf

硕士学位论文 基于颗粒离散元的砂岩渗流时效破裂规律 及应用 Fracture Extension Law of Sandstone under the Case of Time-dependent and Seepage Based on Granular Discrete Element and Its Application 作 者孟凡非 导 师浦 海 教授 中国矿业大学 二 O 一八年五月 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 TD313 学校代码 10290 UDC 622 密 级 公开 中国矿业大学 硕士学位论文 基于颗粒离散元的砂岩渗流时效破裂规律及应用 Fracture Extension Law of Sandstone under the Case of Time-dependent and Seepage Based on Granular Discrete Element and Its Application 作 者 孟凡非 导 师 浦海 教授 申请学位 工学硕士 培养单位 力学与土木工程学院 学科专业 工程力学 研究方向 采动岩体力学与工程 答辩委员会主席 王连国 评 阅 人 二○一八年五月 万方数据 致谢致谢 光阴荏苒，这是我来到徐州的第三个春天，那些关于青春岁月里奋斗的时光 将伴着我进入人生新的旅程。在论文即将完成之际，首先衷心地感谢导师浦海教 授。在我人生重要的科研学习阶段，感谢导师耐心的培养与鼓励，让我在科研的 道路上从最初的幼稚慢慢成长。从论文的选题、技术路线制订、总体构思到最后 成文，每一项工作、每一个环节都凝聚着导师的智慧和心血。在三年的求学生涯 过程中，导师严谨的治学态度，让我体会到了科研工作者的“工匠精神” ；作为 一名年轻学者，导师身上所呈现的科研朝气，一直感染着我，让我在面对科研困 难时依然保持乐观的态度。 在我硕士学习及论文完成阶段，得到了很多师长的指导与教诲，感谢茅献彪 教授、王连国教授、王建国教授、陈占清教授、马占国教授，卢爱红教授、张凯 教授、高亚楠副教授、陆银龙副教授在学习中给予的指导和帮助。感谢力学系所 有的老师，您们不仅传授给我知识，更教会了我学习思考问题的方法，这将是我 一生中最宝贵的财富。 感谢师兄陈家瑞、 肖成、 刘桂宏、 刘鼎、 仇培涛， 师姐曹丽丽， 师弟沙子恒、 陆敬锋、柳森昊、霍兴辉以及倪宏阳在论文完成及生活中给予我的帮助与支持； 感谢张晓东、庞乐、肖天博这几年在学术上给予的鼓励；感谢我的朋友陈爽在我 每一次孤独的时刻，给予我的陪伴与安慰。 求学多年在外，感谢父母、姥姥姥爷以及亲人们一直的惦念和鼓励，让我在 科研道路上坚定的前行，您们的关心与支持一直是我坚强的后盾。特别感谢父母 这么多年来所给与我的最平凡的幸福， 感谢他们教给我生活的道理、 做人的真谛， 感谢他们在我求学生涯中孜孜不倦的付出与支持， 感谢他们用自己的年华岁月为 我做的一点一滴。 感谢论文所引用文献的作者。 最后再次向导师致敬，并感谢所有帮助和关心我的人。 最后衷心地感谢在百忙之中评阅本文以及参加答辩的各位专家、教授， 欢迎 您多提宝贵意见。 2018 年 4 月 万方数据 I 摘摘 要要 一些处于富水区域的煤矿，在采动影响下顶板产生导水裂隙通道，贯通含水 层，诱发突水等矿井灾害事故。当工作面应力调整稳定后，岩体仍然有裂隙不断 产生，此时的顶板时间效应显著。因此研究顶板裂隙通道的形成规律，为顶板事 故的预测以及顶板支护方案提供理论依据，是矿井安全开采的关键之一。本文利 用 PFC-CFD 耦合方法，结合平行黏结应力腐蚀（PSC）模型，建立考虑时间效 应的煤系砂岩渗流数值模型，分析其在不同渗流压力下的损伤演化规律。在此基 础上，将 PFC-CFD-PSC 方法应用于顶板裂隙通道的研究中，对顶板裂隙演化规 律进行分析。主要研究内容及结论如下 （1）基于 PFC-CFD 耦合方法，建立煤系砂岩渗流数值模型，验证了模拟可 靠性，并分析了该模型的裂隙发育规律及其渗流特征。模型的渗透压力越大，内 部产生的微裂隙越多， 且微裂隙分布形式从集中变为分散。 模型的流入压力越大， 不同位置的颗粒骨架受到的流体作用变化范围越大，峰值越大，且峰值都出现在 渗流模型的下部。 （2）利用 FISH 语言编写考虑时间效应的 PSC 模型。分析了不同倾角的初 始裂隙对 PSC 模型裂隙扩展发育规律的影响。根据微裂隙发育个数划分，PSC 模型的损伤演化可分为 3 个阶段初始损伤阶段，损伤演化阶段，破坏阶段。与 常规模型相比， PSC 模型最终破断后的微观裂纹个数少， 且初始裂隙尖端的起裂 角小。 （3）引入 PSC 模型，用来表征时间效应，并与 PFC-CFD 耦合方法的渗流 模型相结合，建立了考虑时间效应的煤系砂岩渗流模型。随着渗透压力的增大， 该模型的贯穿裂纹数量逐渐增多。渗透压力为 0.5MPa、2.5MPa、3.5MPa 时，破 坏形式以剪切破坏为主。当渗透压力为 1.5MPa 时，破坏形式为张拉和剪切共存 的模式。该模型的高水力梯度值集中在岩体骨架上方，形成“环状”结构，在渗 流场底部出现了低压力梯度区域。 （4）为研究采动覆岩顶板的裂隙横向发育规律，利用 PFC-CFD-PSC 方法 建立顶板岩层渗流时效模型。分析覆岩压力、初始裂隙形态与渗流压力对该模型 破断形态的影响，并与常规顶板岩层模型对比。研究发现考虑时间效应的顶板， 扩展裂隙在初始裂隙尖端开始发育，裂隙发育复杂，宏观条数较多，微裂纹发育 阶段少。 该论文有图 65 幅，表 4 个，参考文献 96 篇。 关键词关键词裂隙扩展；颗粒离散元；时间效应；渗流作用 万方数据 II Abstract With the increase of coal mining depth, the rock mass under complex geological conditions is significantly affected by the time effect, and the challenges faced by coal mine safety production are even more severe. For some coal mines that are in water-rich areas, the roof will produce water-conducting fracture channels under the influence of mining, which will penetrate the aquifer, and induce water inrush accidents. Therefore, the study of the ation law of the crack passage in the roof, which provides the theoretical basis for the prediction of the roof accident and the roof support plan, is one of the keys to the safe mining of the mine. In this paper, the PFC-CFD coupling is used to establish a coal-series sandstone numerical model. This model considers the interaction of time effect and seepage, and analyzes the damage evolution law under different seepage pressures. Based on this, the seepage model was applied to the study of fractures in the roof. The main research contents and conclusions are as follows 1 Based on the PFC-CFD coupled , a seepage numerical model of the coal-series sandstone was established. The reliability of the simulation process was verified. The fracture development rules and seepage characteristics of the model were analyzed. The greater the seepage pressure of the model, the more internal microfractures, and the distribution of microfractures from a centralized to a dispersive one. The floating range of the pressure that particles at different positions subjected to increases with the seepage pressure. The larger the seepage pressure, the larger the peak value, and the peak value appears in the lower part of the model. 2 A PSC model considering time effects was written using FISH language. The influence of initial fractures with different dip angles on the development of crack propagation in PSC model was analyzed. The damage evolution of PSC model can be divided into three stages initial damage stage, damage evolution stage, and destruction stage. Compared with the conventional model, the number of micro-fractures after the final breaking of the PSC model is less, and the starting angle of the initial fracture tip is smaller. 3 This paper combining the PSC model with the seepage model, a coal-series sandstone seepage model with time effects was established. The number of fractures in the model gradually increased with the seepage pressure. When the seepage pressure is 0.5 MPa, 2.5 MPa, and 3.5 MPa, the failure mode is mainly shear failure. 万方数据 III When the permeation pressure is 1.5 MPa, the failure mode is the mode of tension and shear coexistence. The high hydraulic gradient of the model is concentrated on the top of the rock, which s a “ring“ structure. A low pressure gradient region appears at the bottom of the seepage field. 4 In order to study the law of lateral development of fractures in overlying strata, a seepage model of roof strata considering time effect was established. The effects of overburden pressure, initial fracture morphology and seepage pressure on the fracture morphology of the model were analyzed which was compared with the conventional roof rock ation model. The study found that the theory of particle discrete element can reveal the failure mechanism of the rock well. The fractures of the roof rock begin to develop at the tip of the initial fracture. The seepage model of the roof rock considering the time effect is complex in the development of fractures, and there are many macroscopic fractures. The angle of cracks developed at the tip of the fracture increases with the seepage pressure. This thesis includes 65 figures, 4 tables and cites 96 references. Keywords fracture propagation; particle discrete element; time effect; seepag 万方数据 IV 目目 录录 摘摘 要要 ........................................................................................................................... I 目目 录录 ........................................................................................................................ IV 图图清单清单 ..................................................................................................................... VIII 表清单表清单 ..................................................................................................................... XIII 变量注释表变量注释表 ............................................................................................................. XIV 1 绪论绪论 ........................................................................................................................... 1 1.1 研究背景及意义..................................................................................................... 1 1.2 国内外研究现状..................................................................................................... 2 1.3 研究内容与技术路线............................................................................................. 7 2 裂隙扩展理论及颗粒离散元方法裂隙扩展理论及颗粒离散元方法 ........................................................................... 9 2.1 裂隙扩展基本理论................................................................................................. 9 2.2 颗粒离散元裂隙扩展模拟方法........................................................................... 14 2.3 颗粒离散元模型宏细观参数关系....................................................................... 21 2.4 本章小结............................................................................................................... 24 3 基于基于 PFC-CFD 耦合方法的砂岩渗流损伤规律耦合方法的砂岩渗流损伤规律 .................................................. 25 3.1 PFC-CFD 耦合计算方法 ..................................................................................... 25 3.2 渗透压力对砂岩裂隙扩展规律的影响............................................................... 30 3.3 本章小结............................................................................................................... 37 4 基于基于 PFC-CFD-PSC 方法的砂岩渗流损伤规律方法的砂岩渗流损伤规律 .................................................. 39 4.1 PSC 模型及参数敏感性分析 .............................................................................. 39 4.2 PSC 模型的裂隙扩展规律 .................................................................................. 44 4.3 基于 PFC-CFD-PSC 方法的砂岩渗流裂隙扩展规律 ........................................ 50 4.4 本章小结............................................................................................................... 54 5 顶板岩层渗流时效破裂规律顶板岩层渗流时效破裂规律 .................................................................................. 56 5.1 顶板渗流时效数值模拟方法............................................................................... 56 5.2 应力作用下顶板岩层裂隙发育规律................................................................... 58 5.3 基于 PFC-CFD-PSC 方法的顶板渗流裂隙发育规律 ........................................ 64 5.4 本章小结............................................................................................................... 69 万方数据 V 6 结论结论 ......................................................................................................................... 71 参考文献参考文献 ..................................................................................................................... 73 作者简历作者简历 ..................................................................................................................... 79 学位论文原创性声明学位论文原创性声明 ................................................................................................. 80 学位论文数据集学位论文数据集 ......................................................................................................... 81 万方数据 VI Contents Abstract ........................................................................................................................ II Contents ..................................................................................................................... VI List of Figures ......................................................................................................... VIII List of Tables ........................................................................................................... XIII List of Variables...................................................................................................... XIV 1 Introduction ............................................................................................................... 1 1.1 Research Background and Significance ................................................................... 1 1.2 Present Research Status ........................................................................................... 2 1.3 Research Contents and Technical Routes ................................................................ 7 2 Crack extension theory and particle discrete-element ............................ 9 2.1 Basic Theory of Crack Extension ............................................................................ 9 2.2 Crack Extension Simulation of Particle Discrete Element ....................... 14 2.3 The Relationship Between Macroscopic and Microscopic Parameter in Particle Discrete Element Model .............................................................................................. 21 2.4 Summary ................................................................................................................ 24 3 Study on Percolation Damage of Sandstone Based on PFC-CFD Coupling ........................................................................................................................ 25 3.1 PFC-CFD Coupling Calculation ............................................................... 25 3.2 Influence of Seepage Pressure on the Law of Fracture extension of Seepage Model in Sandstone ................................................................................................................. 30 3.3 Summary ................................................................................................................ 37 4 Study on Percolation Damage of Sandstone Based on PFC-CFD-PSC ...................................................................................................................................... 39 4.1 PSC Model and Parameter Sensitivity Analysis .................................................... 39 4.2 The Fracture Law of PSC Model ........................................................................... 44 4.3 Fracture Extension of Sandstone Seepage Based on PFC-CFD-PSC ...... 50 4.4 Summary ................................................................................................................ 54 5 Fracture Extension Law of Roof under Influence of Time-dependent and 万方数据 VII Seepage ........................................................................................................................ 56 5.1 Numerical Simulation of Roof Rocks under Time Effect and Seepage ... 56 5.2 The Law of Fracture Extension in Roof Rock under Influence of Stress .............. 58 5.3 Development of Fractures for Roof Seepage and Time-dependent Based on PFC-CFD-PSC ............................................................................................... 64 5.4 Summary ................................................................................................................ 69 6 Conclusions .............................................................................................................. 71 References ................................................................................................................... 73 Author’s Resume ........................................................................................................ 79 Declaration of Thesis Originality ............................................................................. 80 Thesis Data Collection ............................................................................................... 81 万方数据 VIII 图图清单清单 图序号 图名称 页码 图 1-1 研究技术路线 8