深部软弱煤岩巷道松动变形随时间演化规律分析.pdf

分 类 号TD325 密级公开 单位代码10878 学号20133301095 硕士学位论文硕士学位论文 论论 文文题题 目目深部软弱煤岩巷道松动变形随 时间演化规律分析 学学 科科门门 类类工学硕士 学学 科科专专 业业结构工程 研研 究究方方 向向地下结构理论计算与应用 作作 者者姓姓 名名徐盼 导导 师师姓姓 名名吴德义 完完 成成时时 间间2016 年 3 月 万方数据 深部软弱煤岩巷道松动变形随时间演化规律分析 Analysis of deep soft coal and rock loose deation with time evolution 学学 科科门门 类类工学硕士 学学 科科专专 业业结构工程 研研 究究方方 向向地下结构计算理论与应用 作作 者者姓姓 名名徐 盼 导导 师师姓姓 名名吴德义 完完 成成时时 间间2016 年 3 月 万方数据 安徽建筑大学 万方数据 安徽建筑大学 万方数据 安徽建筑大学摘要 I 摘要 随着煤矿开采强度的加大，浅部资源逐渐开采完毕，巷道开挖深度的不断增 加，一大批煤矿已进入深部开采阶段，深部开采带来的难度及问题，已是我国煤 炭行业不得不面对的问题，比如地温高、瓦斯量大、矿压大、支护困难等。煤岩 作为一种岩性较弱的有机岩体，其对应力温度较为敏感，在深部条件下表现为强 烈的流变变形特征。研究表明深部岩石具有持续的强流变特性，表现为变形量 大、持续时间长，即具有明显的时间效应。因此采用科学的研究方法对深部软弱 煤岩的蠕变特性及其变化规律开展研究，确定松动圈范围随时间演化规律，对解 决实际工程中与蠕变相关的问题具有理论和工程实际意义。 本文在综合分析国内外岩石蠕变试验及蠕变数值模拟的基础上， 开展了以下 研究并得出一些结论 （1）采用 SD-20 岩石蠕变仪对煤岩进行单轴分级加卸载蠕变压缩试验，并 通过非线性拟合获取煤岩的蠕变参数。通过对煤岩单轴压缩蠕变试验曲线的分 析，可以看到在较低应力水平下，煤岩试件蠕变由初始蠕变阶段很快进入稳定 蠕变阶段，当应力水平超过其屈服极限时，蠕变进入等速蠕变阶段，随着时间的 增加，应变值逐渐增大，若应变值超过其极限应变值时，试件将发生破坏。 （2）采用有限差分软件 FLAC3D 选择应变软化/硬化模型结合 Burger 蠕变 模型模拟了不同条件下（不同应力、不同断面形状）深部软弱煤岩巷道表面应力 变形随蠕变时间变化规律。模拟结果表明随着应力水平的提高，巷道顶板、底 板及帮部的位移量逐渐增大，但增加幅度逐渐减小；在同一应力水平下巷道表面 位移量总体表现出“帮部位移量大于顶板位移量大于底板位移量”的特点；埋深 较深的巷道表面垂直应力在一定时间内逐渐增大，增长速度先增大再减小，并且 出现垂直应力小幅减小的现象，即产生了应力松弛现象；断面形状对巷道变形影 响较大， 矩形巷道的顶底板及帮部位移量最大， 直墙半圆拱次之， 圆形巷道最小。 （3）在巷道周边 10 个方向上布置监测点，以位移衰减快慢系数作为判断松 动圈厚度的标准确定了不同应力下松动圈范围变化趋势。模拟结果表明在较低 应力水平下，巷道开挖初期，角部松动圈发展滞后于巷道帮部和顶底板，随着蠕 变时间的增加，松动圈形状更加饱满，应力越大，松动圈形状越接近于圆形。 图[83]表[7]参[55] 关键字深部开采，单轴压缩蠕变试验，蠕变数值模拟，松动圈范围 分类号TD325 万方数据 安徽建筑大学Abstract II Abstract With the increasing intensity of coal mining, the shallow resources have gradually depleted and the depth of the tunnel excavation is increasing, a large number of coal mines has entered the stage of deep mining, Chinas coal industry has to face for problems and difficulties what caused by deep mining , such as high ground temperature, gas volume, large underground pressure, supporting difficulties. As a weak organic rock, coal is more sensitive to temperature and stress, in deep conditions showed strong creep deation characteristics. Studies have shown that Deep Rock has sustained strong rheological properties, the perance of large deation, long duration, which has a significant time effect. Therefore, the use of scientific research s on the creep characteristics and variation of deep soft rock of coal to carry out studies to determine the scope of loose circle evolution over time, and has a theoretical and practical engineering to solve practical engineering problems associated with creep. Based on a comprehensive analysis of domestic and foreign rock creep testing machine and creep numerical simulation, carried out the following studies and draw some conclusions 1 Using the SD-20 instrument for rock creep grade coal and rock uniaxial loading and unloading creep compression test, and obtain creep parameters of coal by nonlinear fitting. Through the analysis of coal and rock uniaxial compression creep test curve, you can see at lower stress levels, coal and rock specimens transition from the initial stage and quickly into stable creep stage, when the stress level exceeds its yield the limit, the rock comes into the constant creep stage, the strain increases with time going by, if the strain value exceeds its limit strain value, the specimen will damage; sectional shape of the roadway has the greater inpact on roadway displacement, the displacement of rectangular roadway largest, followed by a curved wall and circular roadway minimum. 2 Using the finite difference software FLAC3D select strain softening / hardening model combines Burger creep model and simulation deep soft coal and rock roadway surface stress and displacement changes with time under different conditions different stresses, different cross-sectional shape. The simulation results show that with the increase of the stress level, the displacement of the roof, floor and floor of the roadway is gradually increased, but the increase is gradually reduced; 万方数据 安徽建筑大学Abstract III roadway surface displacement amount under the same stress level overall exhibit “with the side of displacement greater than the top floor displacement and greater than the amount of displacement“ feature; depth deeper roadway surface vertical stress increases within a certain time, the growth rate transitioned from increases into decreases, and appeared slightly reduced vertical stress phenomena, which produce a stress relaxation phenomenon; 3 Monitoring points are arranged on the periphery of the roadway around 10 directions, taking displacement attenuation coefficient as a standard to determine the changing trend of loosening range of the rock under different stress. The simulation results show that at lower stress levels, the initial tunnel excavation, the corners loose circle of development lags behind the tunnel with the side and the top floor on tunnel excavation initial stage, with the increase of the creep time, the shape of loose circle fuller, the greater the stress , the shape of loose circle more close to the circle shape. Figure[83]table[7]reference[55] Keyworddeep mining，uniaxial compression creep test，numerical simulation of creep，the loosening range of the rock Chinese books catalogTD325 万方数据 安徽建筑大学目录 、 IV 目录 摘要......................................................................................................................................II Abstract................................................................................................................................II 目录....................................................................................................................................IV Contents............................................................................................................................VII 插图清单.........................................................................................................................VIII 插表清单............................................................................................................................XI 第一章 绪论........................................................................................................................1 1.1 研究背景及意义...................................................................................................1 1.2 研究现状...............................................................................................................2 1.2.1 岩石蠕变试验力学特性研究现状...........................................................2 1.2.2 巷道围岩蠕变模拟研究现状...................................................................4 1.2.3 岩石蠕变力学模型研究现状...................................................................5 1.3 研究内容...............................................................................................................6 1.4 技术路线图...........................................................................................................7 第二章 岩石蠕变理论研究...............................................................................................8 2.1 岩石蠕变概述.......................................................................................................8 2.1.1 岩石蠕变的定义........................................................................................8 2.1.2 不同温度、应力条件下蠕变曲线...........................................................9 2.2 岩石蠕变的类型.................................................................................................10 2.3 岩石蠕变模型与本构方程................................................................................11 2.3.1. 线性粘弹塑性流变模型.........................................................................11 2.3.2 非线性粘弹塑性流变模型.....................................................................16 2.3.3 经验公式...................................................................................................18 2.3.4 积分型本构方程......................................................................................19 2.4 岩石蠕变性质的影响因素................................................................................19 2.5 本章小结.............................................................................................................21 第三章 深部煤岩物理力学参数测定与蠕变特性试验..............................................22 3.1 煤岩物理力学参数测定.....................................................................................22 3.1.1 煤岩真密度测定......................................................................................23 3.1.2 煤岩弹性模量、泊松比测定.................................................................23 3.2 煤岩单轴压缩蠕变特性试验.............................................................................25 3.2.1 试验装置...................................................................................................25 万方数据 安徽建筑大学目录 V 3.2.2 试验方法与步骤......................................................................................26 3.2.3 蠕变试验数据的处理方法.....................................................................26 3.2.4 煤岩单轴蠕变试验..................................................................................28 3.2.5 煤岩蠕变模型参数的确定.....................................................................34 3.3 本章小结.............................................................................................................35 第四章 深部软弱煤岩巷道蠕变数值模拟...................................................................36 4.1 FLAC3D 软件简介.............................................................................................36 4.1.1 FLAC3D 软件特点...................................................................................36 4.1.2 FLAC3D计算基本原理.............................................................................36 4.1.3 FLAC3D 内置模型...................................................................................38 4.1.4 FLAC3D 软件分析流程..........................................................................39 4.2 数值建模.............................................................................................................40 4.2.1 数值模型建立的原则..............................................................................40 4.2.2 数值模型的建立......................................................................................40 4.3 数值模型计算与数据处理................................................................................41 4.3.1 不同应力水平下巷道表面蠕变-时间曲线...........................................41 4.3.2 不同应力水平下巷道表面围岩应力分布时间曲线.......................45 4.3.3 不同断面形状巷道表面围岩位移时间曲线....................................51 4.4 本章小结.............................................................................................................53 第五章 深部软弱煤岩巷道松动圈分布随时间演化模拟分析................................. 54 5.1 松动圈理论.........................................................................................................54 5.1.1 围岩松动圈形成原因及物理状态.........................................................54 5.1.2 围岩松动圈的性质..................................................................................55 5.2 数值计算模型的建立与监测点布置...............................................................56 5.3 数值计算结果.....................................................................................................57 5.3.1 应力 P14MPa 时，监测点位移衰减快慢系数及松动圈范围在不同 蠕变时间下的变化分析....................................................................................57 5.3.2 应力 P18MPa 时，监测点位移衰减快慢系数期松动范围在不同蠕 变时间下的变化分析........................................................................................62 5.3.3 应力 P20MPa 时，监测点位移衰减快慢系数及松动圈范围在不同 蠕变时间下的变化分析....................................................................................66 5.4 松动圈发展规律分析........................................................................................71 5.5 本章小结.............................................................................................................74 第六章 结论与展望.........................................................................................................76 万方数据 安徽建筑大学目录 、 VI 6.1 结论......................................................................................................................76 6.2 展望......................................................................................................................77 致 谢..................................................................................................................................78 参考文献............................................................................................................................79 作者简介及读研期间主要科研成果..............................................................................82 万方数据 安徽建筑大学Contents VII Contents Abstract..................................................................................................................................I Contents..............................................................................................................................IV Illustration list...................................................................................................................VII Insert list.............................................................................................................................. X Chapter1Introduction .....................................................................................................1 Chapter2Research of rock creep theory.........................................................................7 Chapter3 Deep coal and rock mechanics parameters measurement and creep properties test...................................................................................................21 Chapter4Numerical simulation of deep soft coal and rock roadway creep..............35 Chapter5 Simulation analysis of deep soft coal and rock roadway loose circle distributed with time evolution...................................................................... 53 Chapter6Conclusion and Prospect................................................................................75 Thank..................................................................................................................................78 Reference............................................................................................................................79 About the Author and the main research during graduate school..................................82 万方数据 安徽建筑大学插图清单 VIII 插图清单 图 2- 1 岩石变形随时间变化曲线（蠕变曲线）...................................................8 图 2- 2 应力或温度变化时，蠕变曲线...................................................................9 图 2- 3 岩石蠕变类型曲线.......................................................................................10 图 2- 4 基本元件示意图...........................................................................................11 图 2- 5Maxwell 模型及其流变曲线........................................................................12 图 2- 6 Kelvin 模型及其蠕变曲线..........................................................................13 图 2- 7 Burgers 模型及其蠕变曲线.........................................................................14 图 2-