Analytical solution for coupled hydro-mechanical modeling of infiltration in unsaturated soils

• Published in: Journal of hydrology (Amsterdam) Vol. 612; p. 128198
• Main Authors: Tracy, Fred T., Vahedifard, Farshid
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2022
• Subjects: Analytical solution; deformation; groundwater; Groundwater modeling; Hydro-mechanical coupling; Infiltration; landslides; saturated hydraulic conductivity; unsaturated flow; Unsaturated soil; Vadose zone; Infiltration; Vadose zone; Unsaturated soil; Groundwater modeling; Analytical solution; Hydro-mechanical coupling
• ISSN: 0022-1694
• DOI: 10.1016/j.jhydrol.2022.128198

•Analytical solution presented for coupled modeling of 1D unsaturated infiltration.•Coupling effect can be significant for depending on soil type and stiffness.•Solution can be used in site-specific or regional analyses of unsaturated soils. Simulating water infiltration in unsaturated soils is an important step in analyzing a wide range of engineering and geosciences applications. The infiltration problem inherently possesses a coupled hydro-mechanical problem in which the unsaturated flow and the soil deformation interact and affect each other. This hydro-mechanical coupling, however, has been ignored in the majority of existing analytical solutions, mainly due to the complexity associated with the mathematical derivation. This paper presents a novel analytical solution for coupled hydro-mechanical modeling of one-dimensional (vertical) infiltration in unsaturated soils. We present an analytical solution for two problems where infiltration is applied at the top boundary as a constant pressure head (first problem) or as a constant flow rate (second problem). A parametric study was performed to examine the effects of hydro-mechanical coupling and various soil parameters on pressure head and strain profiles versus depth. Results reveal that the coupling effect can be pronounced for various values of saturated hydraulic conductivity, Gardner’s α parameter, and Young’s Modulus. The solution can be readily incorporated into site-specific (e.g., groundwater modeling, slope stability) or regional-scale (e.g., landslide mapping) analyses of unsaturated natural and man-made slopes and earthen structures subject to infiltration. Further, the presented analytical framework offers a benchmark for the validation of numerical methods.