Fractures and conduits in the vadose zone can significantly affect the groundwater-surface runoff interaction. Electrical geophysical methods have the potential to provide important information regarding saturation evolution in the fractured vadose zone in the field. Integrating numerical models with the field data can improve the interpretation of the field electrical measurements. In this study we develop and present an advanced method for coupled simulation of variably saturated fluid flow and electrical current distribution in an explicitly fractured porous media. In this model, the fractures are simulated with the hybrid-dimension approach (i.e. 1D fracture elements and 2D matrix elements) discrete fracture matrix model. Mixed hybrid finite element method, previously shown to be significantly more efficient that the conventional finite element method for highly heterogeneous domains, has been used as the numerical method of discretization for both fluid flow and electrical current. The results of the numerical solution are validated by comparing against the results obtained by a finite element based package for three synthetic configurations and the results show that the developed model exceeds the computation performance of the finite element counterpart. The developed model is then used to investigate impact of fracture geometry and the influence of electrical dipole configurations on the simulated electrical response. This work is the preliminary study of a highly efficient new tool for the coupled simulation of water flow and electrical current in fractured vadose zone.

中文翻译：

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一种用于骨折包气带水流和电流耦合模拟的离散断裂模型


包气带的裂缝和管道会显著影响地下水-地表径流的相互作用。电学地球物理方法有可能提供有关现场断裂包气带饱和度演变的重要信息。将数值模型与现场数据集成可以改进对现场电气测量的解释。在这项研究中，我们开发并提出了一种先进的方法，用于耦合模拟显式裂隙多孔介质中可变饱和流体流动和电流分布。在该模型中，使用混合维度方法（即 1D 裂缝单元和 2D 矩阵单元）离散裂缝矩阵模型模拟裂缝。混合混合有限元方法，以前被证明比高度异质域的传统有限元方法效率高得多，已被用作流体流动和电流离散化的数值方法。通过与基于有限元的包对三种合成配置获得的结果进行比较，验证了数值解的结果，结果表明，开发的模型超过了有限元对应模型的计算性能。然后使用开发的模型研究裂缝几何形状的影响以及电偶极子构型对仿真电响应的影响。这项工作是对骨折包气带水流和电流耦合模拟的高效新工具的初步研究。