Impact of Nondiagonal Elements of Hydraulic Conductivity Tensor on Seepage through Anisotropic Soils

According to Darcy, Darcy’s velocity is proportional to the hydraulic gradient via hydraulic conductivity. Darcy’s law was initially developed to calculate the one-dimensional flow velocity through porous media. Darcy’s law has since been generalized by the scientific community to analyse 2D and 3D seepage flow. Because hydraulic gradient, and Darcy’s flow velocity are vectors hydraulic conductivity needs to be treated as a scalar for isotropic soils and or a tensor for anisotropic soils. In general, the tensor has three categories of major, intermediate, and minor principal hydraulic conductivity scalar values where the minor principal orientation is normal and the major and intermediate principal ones are aligned within the soil stratigraphic plane. Since, the soil is generally axisymmetric on mesoscale, within stratigraphic planes major and intermediate principal hydraulic conductivities are generally equal. In a case where the seepage is analysed in the orthogonal system of coordinates aligned with the three principal orientations of the tensor (e.g., stratigraphic and XY planes are both horizontal), the tensor can be assumed diagonal. In this paper, a 2D finite-difference numerical model developed using the MATLAB interface, capable of simulating seepage through anisotropic soils employing a full nondiagonal hydraulic-conductivity tensor, to examine and analyse the characteristic impacts of considering nondiagonal tensors due to various degrees of stratigraphic tilt with respect to system of coordinates.