基于离散裂隙网络模型的裂隙水渗流计算

离散裂隙网络模型(Discrete Fracture Network（DFN）)是研究裂隙水渗流最为有效的手段之一。文章根据裂隙几何参数和水力参数的统计分布，利用Monte Carlo随机模拟技术生成二维裂隙网络，基于图论无向图的邻接矩阵判断裂隙网络的连通，利用递归算法提取出裂隙网络的主干网或优势流路径。基于立方定律和渗流连续性方程，利用数值解析法建立了二维裂隙网络渗流模型，分析不同边界条件下裂隙网络中的流体流动。结果表明，该方法可以模拟区域宏观水力梯度和边界条件下，裂隙网络水力梯度方向总的流量，以及节点的水位、节点间的流量和流动方向的变化特征，为区域岩溶裂隙水渗流计算提供了一种实用、可行的方法。 

Computation of fracture water flow based on discrete fracture network model

Discrete fracture network (DFN) model is one of the most effective means to study the flow path and groundwater flow in a fractured rock aquifer. Based on statistical distributions of geometrical and hydraulic parameters of fractures, two-dimensional discrete fracture network is realized through using Monte Carlo stochastic simulation technology. Fracture network connectivity is determined based on adjacency matrix of undirected graph and backbone or distinct preferential flow path is preserved using recursive algorithm. Flow model of DFN is built using numerical-analytical method on the basis of cubic law and seepage continuity equation; and this model is used to solve fluid flow under different boundary conditions. The results show that this method can simulate the total flux into the regional domain in the direction of hydraulic gradient, head at internal nodes and flow in channels as well as variation of flow direction at internal nodes. It provides a practical and feasible method for flow estimation of regional karst fissure water.