考虑表面粗糙特性的三维交叉裂隙渗流机理研究

Advances in Geo-Energy Research, 2018, 2(2): 113-121

原文网址：http://www.astp-agr.com/index.php/Index/Index/detail?id=54

         随着地下空间的利用、能源存储和核废料处理设施等地下工程的兴起，裂隙岩体的渗流特性日益成为岩石力学研究领域的热点。裂隙岩体渗流非常复杂，受诸多因素影响，如：温度、应力及裂隙的几何特征等。其中，单个交叉裂隙的力学和几何性质的描述是理解裂隙岩体内的渗流变形性质的基础。

      最近，中国矿业大学刘日成副研究员与日本长崎大学蒋宇静教授等合作，在考虑表面粗糙特性的三维交叉裂隙渗流机理方面取得新进展。他们通过建立具有不同表面粗糙度的三维交叉裂隙模型，自编程序，形成了考虑剪切作用下的三维交叉裂隙渗流计算的数值方法。数值模拟结果揭示了三维交叉裂隙面在剪切过程中开度、流通路径以及渗透系数的演化规律，阐明了裂隙表面粗糙度对裂隙相交处流量再分布特征的影响，明确了粗糙裂隙模型和平行平板裂隙模型渗透特性的差异，得到了三维交叉裂隙岩体的剪切特性及流动机理，为进一步对自然裂隙岩体渗透特性的理解和把握提供理论研究基础。成果发表在Advances in Geo-Energy Research 2018年第二期上。

Hydraulic properties of 3D crossed rock fractures by considering anisotropic aperture distributions

Richeng Liu, Yujing Jiang, Na Huang, Satoshi Sugimoto

(Published: 2018-03-09)

CorrespondingAuthor and Email:  Richeng Liu, liuricheng@cumt.edu.cn

Citation: Liu, R., Jiang, Y., Huang, N., Sugimoto, S. Hydraulic properties of 3D crossed rock fractures by considering anisotropic aperture distributions. Advances in Geo-Energy Research, 2018, 2(2): 113-121, doi: 10.26804/ager.2018.02.01.

ArticleType: Original article

Abstract：

     This study presents a numerical study on the geometrical and hydraulic properties of a three-dimensional intersected fracture model that is a fundamental element involved in complex fracture networks. A series of rough fracture surfaces were generated using the modified successive random additions (SRA) algorithm. Different shear displacements were applied to the fracture to obtain the anisotropic aperture fields that will be further assigned to the two fractures in the intersected fracture model. The flow was calculated using the Reynolds equation with the continuity conditions addressed at intersection part between the two fracture planes. The evolutions of the aperture distributions, flow channels and equivalent permeability were estimated. The simulation results reveal that as the shear displacement and joint roughness coefficient (JRC) increase, the aperture increases anisotropically, which causes significant fluid flow channeling effects. The main flow channels change from being concentrated in one fracture to the other fracture during the shear, accompanied by the change of the flow rate ratios between two flow planes at the inlet/outlet boundary.

     During the shear the average contact area accounts for approximately 4% to 15% of the fracture planes, and the actual calculated flow area is about 35% to 42% of the fracture planes, which is smaller than the noncontact area. As the shear displacement and JRC increase, the equivalent permeability of the intersected fracture increases. Therefore, the channeling flow should be considered to interpret the fluid flow through the rough fractures even in the simplest fracture networks.

Keywords:  Intersected fracture, Shear displacement, Roughness, Channeling flow

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