有自由面渗流问题的等效裂隙网络模型  

Equivalent fracture network model for seepage problem with free surface

作　　者：闯喜宏 樊鑫成 秦慧凯 CHUANG Xihong;FAN Xincheng;QIN Huikai(GD Power Development Co.,Ltd.,Beijing 100101,China;School of Resources and Environmental Engineering,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]国电电力发展股份有限公司,北京100101 [2]武汉科技大学资源与环境工程学院,湖北武汉430081

出　　处：《人民长江》2024年第3期184-189,共6页Yangtze River

基　　金：水资源与水电工程科学国家重点实验室(武汉大学)开放研究基金项目(2019SGG04)。

摘　　要：为降低传统连续介质渗流模型的网格依赖性并提升数值计算稳定性,基于连续介质渗流模型,通过引入表征单元体将均匀多孔介质水平和竖直孔隙概化为正交裂隙网络,建立了有自由面渗流问题的等效裂隙网络模型。推导了等效裂隙网络模型的渗流速度、连续性方程及边界条件的等效形式,将二维渗流问题转化为一维等效裂隙网络渗流问题。结合连续型罚Heaviside函数,将湿区渗流流速扩展至整个研究区域,给出了等效裂隙网络渗流分析的有限元求解格式。通过与均质矩形坝和梯形坝其他数值解的对比分析,验证了等效裂隙网络模型的有效性。最后将该方法应用于土质斜心墙坝稳定渗流分析,计算结果很好地反映了黏土心墙防渗体与上下游坝壳堆石区的自由面分布规律,揭示了黏土心墙防渗体的阻水效应。In order to reduce the grid dependence of traditional continuum medium seepage model and improve stability of numerical calculation,based on the continuum medium seepage model,the horizontal and vertical pores in the uniform porous media were generalized as orthogonal fracture networks by introducing the representative elementary volume,and an equivalent fracture network model for free surface seepage problems is established.The equivalent form of seepage velocity,continuity equation and boundary conditions were derived.The two dimensional seepage problem was transformed into one dimensional seepage problem of equivalent fracture network model.Combining with the continuous penalty Heaviside function,the flow velocity in wet zone was extended to the whole flow domain and the finite element formulation was presented.The validity of the equivalent fracture network model was verified by comparing it with the numerical solutions of homogeneous rectangular and trapezoidal dams.Finally,the proposed method was applied to the sensitivity analysis of the permeability coefficient of a zoned dam with clay core and sand shell.The distributions of the free surface in the clay core and the upstream and downstream sand shells were well presented and the water blocking effect of the clay core was also demonstrated.

关 键 词：等效裂隙网络模型 自由面 稳定渗流 表征单元体 

分 类 号：TV871[水利工程—水利水电工程]