破碎岩体中非达西渗流细观机理的分形研究

According to the high porosity, high permeability, and fractal distribution characteristics of broken rock, this project will combine the fractal geometry theory and technology in nonlinear mathematics with the dynamics of fluids in porous media, and establish a fractal mathematical model for Non-Darcy seepage characteristics of the broken rock. For loose and load broken rock ,original location fractured rock mass, this project respectively puts forward new research methods which is combined capillary and panel gap flow with pore throat, the affecting mechanism and key technical scheme of non-Darcy factor are revealed. The non-Darcy factor is expected to a function of fractal dimension, porosity, particle size, shape, pore throat ratio, load conditions, cracks structure parameters and so on. The effect of various factors on the non-Darcy flow is quantified. The analytic expression of the non-Darcy factor is got. The fractal results will compared with the experimental data, the traditional model, and the numerical simulation，to verify the validity of the model. This project will help us to understand the transport law of porous media which has high porosity and high permeability, to make up the existing research theory of high speed flow，to solve the hypertonic problem of mining, petroleum, groundwater and geology engineering, to expand the practical application of the nonlinear flow field.

根据破碎岩体孔隙率大、渗透性强、满足分形分布的特点, 本课题将非线性数学中的分形几何理论和技术与多孔介质流体动力学相结合，拟建立一套完整的描述破碎岩体非达西渗透特性的分形数学模型。针对堆积（松散、承压）破碎岩体和原位破碎岩体，分别提出了毛细管和平板隙缝流与孔喉相结合的新研究方法,揭示多孔介质微观结构对非达西因子的影响机理和关键技术方案。拟建立非达西因子和孔隙度，颗粒的大小、形状，孔喉比，负载情况，以及裂缝结构参数等的函数关系，量化各种因素对非达西渗流的影响，得到非达西因子的解析表达式。分形模型预测值将与实验结果，传统模型，以及数值模拟结果对比，验证模型的有效性。本项目的开展有助于进一步深刻理解和认识孔隙率大、渗透率高的多孔介质的输运规律，弥补现有理论中对高速渗流研究的不足，解决采矿工程、石油工程、地下水工程和工程地质等领域的高渗问题，拓展非线性渗流的实际应用领域。

项目按照原计划顺利完成预期目标，已发表学术论文11篇，其中SCI检索3篇，EI检索1篇；参加了国内学术会议两次，国际学术会议两次。基于破碎岩体的孔隙度大、渗透性强、满足分形分布的特征，建立了三种描述破碎岩体非达西渗流的阻力模型，即平均水力半径孔喉模型、分形孔喉模型和分形绕流阻力模型。分形绕流阻力模型，证明绕流阻力模型结合分形理论也可用于描述流体在多孔介质中的流动;分形孔喉模型揭示了分形维数，迂曲度等对破碎岩体非达西渗流的影响;平均水力半径孔喉模型修正了Ergun方程，通过对比平均水力半径孔喉模型和Foechheimer方程，得到了非达西因子和非达西等效渗透率的表达式，以及非达西等效渗透率和达西渗透率的比值，提出岩体达西和非达西渗流的分界雷诺数是0.1。将平均水力半径孔喉模型扩展到气液两相流，得到了达西渗透率，非达西因子，非达西等效渗透率的表达式，以及相对达西渗透率、相对非达西因子的表达式。还将三种Forchheimer型非达西渗流理论引入到矿井水害防治中，分别得到突水临界阈值，为矿井水害防治提供一定的理论依据。本项目还开展了矿井导水危险性定量评价研究和突水机理研究。