煤系砂岩渗流—蠕变损伤破裂机理及其分数阶模型研究

发布时间：2018-03-07 12:50

本文选题：煤系砂岩　切入点：渗流-蠕变　出处：《中国矿业大学》2017年博士论文　论文类型：学位论文

【摘要】：随着煤矿进入深部开采阶段,复杂地质环境条件下煤岩体流变特性显著,巷道围岩稳定控制更加困难,煤矿安全生产所面临的挑战更加严峻。特别地,对于一些处于富水区域的煤矿,地下水渗流作用加快了巷道围岩的变形,围岩内部裂隙发育极易导致地下水涌入巷道,诱发突水等矿井灾害事故。煤岩介质渗流-蠕变损伤破裂特征及其蠕变模型研究是实现巷道围岩稳定性控制的理论基础。本文设计并组建适合完整岩石试样渗流-蠕变耦合试验系统,以典型煤层顶板砂岩为研究对象,结合扫描电镜SEM试验,从宏观与细观两个层面系统研究渗流作用下砂岩蠕变损伤破裂机理,基于分数阶微积分理论,建立相应的渗流-蠕变模型。主要取得以下研究成果:(1)对煤系砂岩开展四种情况下的渗流-蠕变耦合试验,获得砂岩蠕变特性曲线,研究渗透压力与围压对砂岩蠕变特性及渗透特性的影响,明确砂岩最大蠕变量、不同阶段蠕变变形速率、渗透速率、渗透率等参数的变化规律。(2)系统研究砂岩渗流-蠕变破坏的宏观特征,如宏观破坏方式、破裂面粗糙度等;基于扫描电镜SEM试验,获得不同条件下砂岩渗流-蠕变破坏断口细观特征形貌,分析砂岩损伤断裂模式随围压与渗透压力的演化规律;建立砂岩局部细观断裂与宏观破坏之间的联系,揭示渗流作用下砂岩蠕变断裂机制。(3)基于岩石蠕变理论、分数阶微积分理论,以基本力学元件为基础,按照串并联法则,建立煤系砂岩整数阶与分数阶非线性粘弹塑性三维蠕变模型,基于太沙基应力原理,建立煤系砂岩整数阶与分数阶渗流-蠕变模型,利用最小二乘法确定模型参数,对整数阶与分数阶模型的精度进行评价。(4)基于分布阶微积分理论,应用单元网络思想,以分布阶粘壶为基础,建立分布阶三参量固体模型,通过具体算例分析岩石材料的流变特性;以单个含损伤的分数阶粘壶为基础,提出含损伤分布阶粘壶,以整数阶西原模型为基础,建立含损伤的分布阶西原模型,通过具体算例,分析煤系砂岩的损伤蠕变特性。研究结论可为深部富含水域煤矿巷道围岩稳定性控制及突水灾害等防治提供理论依据。
[Abstract]:With the coal mine entering the stage of deep mining, the rheological characteristics of coal and rock mass are obvious under the complex geological environment, the stability control of roadway surrounding rock is more difficult, and the challenge of coal mine safety production is more severe. For some coal mines in water-rich areas, the seepage of groundwater accelerates the deformation of surrounding rock of roadway, and the development of cracks in surrounding rock can easily lead to the influx of groundwater into roadway. The characteristics of percolation and creep damage and fracture characteristics of coal and rock media and their creep model are the theoretical basis for the stability control of roadway surrounding rock. This paper designs and sets up a seepage model suitable for intact rock samples. -creep coupled test system, Taking the typical coal seam roof sandstone as the research object and combining with the SEM test of scanning electron microscope, the creep damage and fracture mechanism of sandstone under percolation is systematically studied from macroscopic and meso levels, based on fractional calculus theory. A corresponding seepage creep model was established. The following research results were obtained: 1) the seepage creep coupling test was carried out on coal-measure sandstone under four conditions, and the creep characteristic curve of sandstone was obtained. The influence of permeability pressure and confining pressure on the creep and permeability characteristics of sandstone is studied. The maximum creep amount of sandstone, the creep deformation rate in different stages and the permeability rate are determined. This paper systematically studies the macroscopic characteristics of seepage and creep failure of sandstone, such as the macroscopic failure mode, the roughness of fracture surface and so on, based on the SEM test of scanning electron microscope, The microscopic morphology of sandstone seepage creep failure fracture is obtained under different conditions, the evolution law of sandstone damage fracture model with confining pressure and permeability pressure is analyzed, and the relationship between local meso-fracture and macroscopic failure of sandstone is established. It is revealed that the creep fracture mechanism of sandstone under seepage action is based on rock creep theory, fractional calculus theory, based on basic mechanical elements, according to series-parallel rule, The integral order and fractional order nonlinear viscoelastic-plastic creep model of coal-measure sandstone is established. Based on the terashage stress principle, the integral order and fractional order percolation creep model of coal-measure sandstone is established, and the model parameters are determined by the least square method. The accuracy of integral order and fractional order model is evaluated. (4) based on the theory of distributed order calculus, the distributed order three parameter solid model is established based on the idea of unit network and based on the distributed order sticky pot. The rheological characteristics of rock materials are analyzed by a concrete example. Based on a single fractional-order viscometer with damage, the paper presents a new model of distribution-order viscometer with damage, which is based on integer order western-primitive model. The damage and creep characteristics of coal-measure sandstone are analyzed by an example, and the results can provide theoretical basis for the control of surrounding rock stability and water inrush disaster in deep and rich water mine roadway.
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD313

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