岩体裂隙网络非稳定渗流分析与数值模拟

针对裂隙岩体的非稳定渗流问题，通过将Darcy定理扩展到包含干区的整个裂隙网络区域，并令潜在溢出边界条件为Signorini型互补边界条件，将湿区上的非稳定渗流问题转化为全域上的一个新的初边值问题。为降低试探函数选取的难度，建立与定义在整个裂隙网络区域上的偏微分方程（PDE）提法等价的抛物型变分不等式（PVI）提法，并给出裂隙网络非稳定渗流分析的有限元数值分析格式和迭代算法，与砂槽模型试验数据的对比分析，验证其有效性。最后，将文中发展的计算方法应用到含复杂裂隙网络的边坡非稳定渗流分析，计算结果很好地反映出边坡内部自由面随库水降落的变化规律，并能准确地描述裂隙网络内部渗流运动特征及流量分布的不均匀性。

Formulation and simulation of non-steady seepage flow through fracture network in rock masses

By extending Darcy’s law to dry domain above the free surface and specifying a Signorini’s type of boundary condition on the potential seepage boundaries, a new initial-boundary value problem of entire domain is deduced from non-steady seepage flow problems with free surface of in fractured rock masses. A parabolic variational inequality(PVI) formulation equivalent to the partial differential equation(PDE) is proposed for reducing the difficulty in selecting trial functions, while the finite element discretization and iterative algorithm of the PVI formulation are detailed. The validity of the numerical approach is then verified by existing laboratory tests. Finally, as an application to the non-steady seepage flow analysis in rock slope including complex fracture networks, the calculation results well illustrate the variations of free surfaces during drawdown of reservoir water level; characteristics of seepage flow movement in fracture networks and inhomogeneity of flow distribution at seepage surfaces.