裂隙岩体三维渗流网络饱和/非饱和、非恒定渗流分析

Saturated/unsaturated,unsteady seepage analysis of three dimensional network in the fractured rock mass

采用离散裂隙网络模型研究裂隙岩体非饱和渗流问题,能够比较真实地反映裂隙网络中的实际渗流状态。目前,三维裂隙网络研究非饱和渗流存在2个关键问题,即渗流网络构建问题和渗流网络网格剖分问题。针对这些问题,通过改进现有三维块体切割算法、增加渗流面阻水特性判断等模块,形成裂隙岩体三维渗流网络搜索算法,为构建三维渗流网络奠定基础;将这些裂隙面片视为限定条件,利用限定Delaunay三角剖分技术就可解决因形态复杂而导致的网格难以剖分问题;根据非饱和渗透参数和饱和渗透参数的关系函数,利用伽辽金法建立裂隙网络饱和/非饱和非恒定渗流分析的有限元方程。经典型算例验证,裂隙网络中水流流动方向符合实际的流动方向,各测点达到稳态时水头计算值与实测水头值基本吻合,误差最大不超过1.07%。这表明,该方法不仅能够产生客观正确的渗流网络,还能够产生合理的计算网格;另外,计算结果所反映的水流变化规律能够比较准确地再现裂隙网络中实际水流的流动趋势和运动规律。

Unsaturated seepage in fractured rock is common in nature,which can be studied by a discretefracture network model,reflecting the actual flow state in fracture network. Currently,there are two key is-sues in the research on unsaturated seepage in fractured rock,namely,the generation of seepage networkand mesh generation of seepage network. To these problems,three-dimensional fractured rock flow networksearch algorithm was formed by improving the existing three-dimensional block cutting algorithm and increas-ing the judgment of waterproof properties of fracture,etc. The problem of mesh generation caused by irregu-lar fracture was solved by constraining Delaunay triangulation technique,in which these fractures are seenas restrained conditions. Then based on the relationship function between unsaturated seepage parameter andunsaturated seepage by Prof. Zhang,the finite element equation was established by Galerkin method on sat-urated/unsaturated unsteady seepage analysis of fractured rock network. It was proved that the direction ofwater flow in fracture network was in accordance with realistic flow direction,and the calculated values ofmeasuring point head water was in well keeping with measured values in steady state,with the maximumerror less than 1.07%,which shows that the method could not only produce objective and accurate percola-tion network,but also could generate a reasonable computational mesh;and the calculations reflecting thechanges of water flow could accurately reproduce the actual fracture network trends in water flow and move-ment rules.