破碎煤岩体流固耦合渗流稳定性试验研究

发布时间：2018-04-15 05:38

本文选题：破碎煤岩体 + 流固耦合　；参考：《西安科技大学》2017年硕士论文

【摘要】：随着煤炭开采深度的增加,越来越多的矿井面临突水或煤与瓦斯突出等动力灾害的威胁,此类动力灾害的发生常与水、瓦斯在破碎煤岩体中的渗流密切相关。因此,对于破碎煤岩体流固耦合渗流规律的研究成为突水或煤与瓦斯突出灾害防治的基础课题。本文采用室内试验、理论分析及数值模拟相结合的方法,研究了破碎煤岩体流固耦合渗流规律,取得如下研究成果:(1)开展了分级加载下破碎煤岩体的渗流试验,给出了各级轴向荷载下孔隙率随时间的变化规律;定义了描述渗流速度变化程度的参数Dv,且给出了该参数与有效应力的关系式;得到了不同粒径破碎煤岩体试样的渗透特性参量及蠕变参数变化规律。(2)利用自主研发的破碎岩石三轴渗流试验系统,测试了三轴应力下破碎煤岩体渗透特性,结果表明三轴应力下破碎煤岩体的渗流规律符合Forchheimer关系;推导了渗流速度与有效应力之间的关系;得到了破碎煤岩体围压与渗透率的变化规律,且可用指数型公式k= aebσ3描述;分析了三轴应力下破碎煤岩体孔隙率对渗透特性的具体影响。(3)基于试验结果与理论分析,建立了破碎煤岩体流固耦合渗流动力学模型,利用解耦方法对模型进行简化,得到破碎煤岩体渗流系统的总平衡态,结合试验现象及结果,给出了破碎煤岩体发生渗流失稳的条件,得到了破碎煤岩体渗流失稳的临界压力梯度值,可为矿井突水或煤与瓦斯突出等动力灾害的预防提供参考。(4)采用数值模拟方法,对破碎煤岩体流固耦合渗流动力学模型进行求解,数值模拟计算结果中的孔隙压力、孔隙率、渗透率及非Darcy流β因子等参量的变化规律与试验得到的变化规律基本吻合,文中建立的流固耦合渗流动力学模型可用于描述破碎煤岩体的渗流行为。
[Abstract]:With the increase of coal mining depth, more and more mines are faced with the threat of water inrush or coal and gas outburst. The occurrence of such dynamic disasters is often closely related to the seepage of water and gas in broken coal and rock mass.Therefore, the study of fluid-solid coupling seepage law of broken coal and rock mass becomes the basic subject of water inrush or prevention of coal and gas outburst disaster.In this paper, laboratory tests, theoretical analysis and numerical simulation are used to study the fluid-solid coupling seepage law of broken coal and rock mass. The following research results are obtained: 1) the seepage test of broken coal and rock mass under graded loading is carried out.The variation of porosity with time under various axial loads is given, the parameter of the variation degree of seepage velocity is defined, and the relationship between the parameter and the effective stress is given.The permeability characteristic parameters and creep parameters of broken coal and rock mass samples with different particle sizes are obtained. The permeability characteristics of broken coal and rock mass under triaxial stress are tested by using the self-developed triaxial seepage test system.The results show that the percolation law of broken coal and rock mass under triaxial stress accords with Forchheimer relation, deduces the relationship between seepage velocity and effective stress, obtains the variation law of confining pressure and permeability of broken coal and rock mass, and can be described by exponential formula k = aeb 蟽 3.Based on the experimental results and theoretical analysis, a hydrodynamic model of fluid-solid coupling seepage of broken coal and rock mass is established, and the model is simplified by decoupling method.The total equilibrium state of the seepage system of broken coal and rock mass is obtained. Combined with the experimental phenomena and results, the condition of seepage instability of broken coal and rock mass is given, and the critical pressure gradient of seepage instability of broken coal and rock mass is obtained.It can provide a reference for the prevention of mine water inrush or coal and gas outburst. The numerical simulation method is used to solve the hydrodynamic model of fluid-solid coupling seepage of broken coal and rock mass. The pore pressure and porosity in the numerical simulation results are obtained.The variation of permeability and 尾 factor of non- flow is basically consistent with the experimental results. The fluid-solid coupled seepage dynamic model can be used to describe the seepage behavior of broken coal and rock mass.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD315

【参考文献】