基于三维形貌的错动节理非线性渗流特性研究

Nonlinear Flow Characteristics in Non-mated Rock Fractures Considering 3D Definition of Fracture Surfaces

岩石结构面形貌对可变形岩石节理中的渗透特性具有重要影响。为了研究可变形岩石节理中三维形貌对其渗透特性的影响展开了人工错动节理渗透特性实验。实验采用常法向荷载条件,法向荷载采用1.0~5.0 MPa。基于颗粒粗细,选取了三种花岗岩试样进行人工劈裂得到实验试样。采用一种三维形貌参数表征其粗糙度。基于实验结果,分析了节理中的非线性渗透规律,讨论了临街雷诺数及Forchheimer方程,并提出了错动节理中的非线性渗流公式。将提出的公式与已有的研究成果对比分析,包括Forchheimer方程、Izbash经验模型等。讨论了各模型的优缺点。通过对比可知,提出的公式考虑了三维形貌参数,可以看做是对Izbash经验模型的一种扩展,形式上简单,具有重要的工程价值。

Three-dimensional（ 3 D） morphology of rock fracture has a great influence on its hydraulic behavior. Experiments of water flow through rock joints are conducted to experimentally investigate the 3 D roughness dependent non-linear flow characteristics in deformable rock fractures. The normal loads range from 1. 0 MPa to 5. 0 MPa. Granite samples with different grain thickness are selected. 3 D morphology parameter is used to describe the joint surface. The non-linear flow characteristics are analyzed. Forchheimer ＇ s equation and the critical Reynolds number are discussed. A new equation is proposed to describe the non-linear flow in rock fracture. In addition,the proposed formula is compared with existing models including Lomize ＇ s equation,Forchheimer equation and Izbash ＇ s law. The advantages and disadvantages of these models are analyzed in detail. The results show that the proposed equation considering 3 D morphology is easier in the structure. It can be seen as an extension of the Izbash＇s law and has important engineering values.