考虑裂隙-岩块间水交换的单裂隙非饱和渗流数值模拟  

Numerical Simulation of Unsaturated Flow in Single Fracture Considering the Water Exchange Between Fracture and Matrix

作　　者：钟振[1] 胡云进[1] 刘国华[1] 

机构地区：[1]浙江大学水工结构与水环境研究所,浙江杭州310058

出　　处：《四川大学学报（工程科学版）》2012年第4期51-56,共6页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家自然科学基金资助项目(50809059);水体污染控制与治理科技重大专项资助项目(2009ZX07424-004)

摘　　要：为了研究单裂隙非饱和渗流的水力特性,根据裂隙面分形维数、裂隙面位错值和面积接触率,提出了采用随机布朗函数生成裂隙开度分布的方法;基于裂隙局域立方定理成立的假定,并考虑裂隙-岩块间拟稳态水交换,建立了单裂隙非饱和渗流数值分析模型。模拟得到的裂隙毛细压力-饱和度以及非饱和渗透系数-毛细压力的关系曲线能够反映排水、吸水间的滞后性及体现排水时的进气值和残余水饱和度。模拟结果与试验结果的定性对比表明,建立的模型可为考虑裂隙-岩块间水交换的单裂隙非饱和渗流模拟提供合理可行的方法。最后对比了考虑与不考虑裂隙-岩块间水交换的裂隙非饱和渗透系数-毛细压力关系曲线,结果表明,在高毛细压力(低饱和度)下,可忽略裂隙-岩块间的水交换。In order to study the hydraulic characteristics of unsaturated flow in single fracture, a method for generating the distribution of fracture aperture using Weierstrass-Mandelbrot function was proposed according to fractal dimension,dislocation value and contact area of fracture surface. Based on the assumption that a parallel-plate approximation can stand in the subregion of the fracture ,a numerical model for simulating unsaturated flow in single fracture considering the quasi-static water exchange between fracture and matrix was built up. The simulated relationships between capillary pressure and saturation and between unsaturated hydraulic conductivity and capillary pressure of fracture could be used to describe the hysteresis during drainage and imbibition and figure out the air-entry value and the residual water saturation during drainage. The qualitative comparison of simulated results and experimental results Showed that the proposed model is fea- sible and reliable in modeling the unsaturated flow in single fracture considering the water exchange between fracture and matrix. Finally, comparisons of relation curve between unsaturated hydraulic conductivity and capillary pressure by taking water exchange into account or not was conducted. The result showed that the fracture-matrix exchange is negligible under high capillary pressure （low saturation）.

关 键 词：水交换 单裂隙 非饱和渗流 数值模拟 

分 类 号：TV554[水利工程—水利水电工程]