Location: Agroclimate and Hydraulics Research UnitTitle: Prediction of earth dam seepage using a transient thermal finite element model
Submitted to: Water
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/3/2023
Publication Date: 4/6/2023
Citation: Wise, J.L., Hunt, S., Al Dushaishi, M. 2023. Prediction of earth dam seepage using a transient thermal finite element model. Water. 15(7). Article 1423. https://doi.org/10.3390/w15071423.
Interpretive Summary: Approximately sixty percent of federally sponsored earthen dams constructed by the United States Department of Agriculture-Natural Resources Conservation Service (USDA-NRCS) have exceeded their planned service life. Seepage is a common failure mechanism of earthen dams. Numerically predicting seepage is complex due to complicated geometries, changing water heights, and complex failure analysis. A model is proposed that relates heat flow to fluid flow through soil with respect to time. The model is verified mathematically to be accurate. A sensitivity analysis of the soil and water properties is performed and shows that seepage is only dependent on the soil and not on water.
Technical Abstract: With the majority of United States Department of Agriculture-Natural Resources Conservation Service (USDA-NRCS) sponsored earthen dams exceeding their planned service life, seepage is a concern since it is a common failure mechanism among earthen dams as a whole. Seepage occurs when water penetrates a hydraulic barrier to create open pathways, channels, or piping leading to internal erosion or stability issues due to increased effective stress. Due to the complex geometries of these hydraulic structures, time-dependent boundary conditions, and complicated failure analyses, researchers have used numerical approaches to estimate seepage. However, the existing numerical models are either computationally expensive or assume steady state conditions. This work develops the framework for using a transient thermal finite element analysis (FEA) model to predict transient seepage. The FEA model is compared to an analytical transient heat partial differential equation to verify the approach. A sensitivity analysis of the FEA model shows that the time aspect of seepage flow is dependent on the medium (soil) and not on the fluid properties.