Date of Graduation

8-2017

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering (MSCE)

Degree Level

Graduate

Department

Civil Engineering

Advisor/Mentor

Wood, Clinton M.

Committee Member

Prinz, Gary S.

Second Committee Member

Bernhardt, Michelle L.

Keywords

Dam; Geophysics; Levee; Non-destructive; Resistivity; Surface Waves

Abstract

Geophysical methods including Capacitively-Coupled Resistivity (CCR), Electrical Resistivity Tomography/Imaging (ERT/ERI), Multichannel Analysis of Surface Waves (MASW) with Love and Rayleigh waves and a Full-Waveform Inversion (FWI) were performed on Kinion Lake Dam, an earth-filled embankment dam that has historically experienced significant seepage and internal erosion issues. Surveys were completed along the crest and downstream toe of the dam. Results from the surveys indicate that each method is capable of resolving the bedrock depth within 1-2 m of locations shown on previous drilling logs, though some discrepancies between the methods exist. A weathered bedrock layer is believed to have led to the different depths between the methods. Rayleigh wave MASW and FWI were determined to be most effective at determining bedrock depth at deeper bedrock locations (i.e., the dam crest) and Love wave MASW was the only viable seismic method at detecting bedrock for areas with thin soil layers and complex bedrock geometry (i.e., the dam toe). The CCR and ERI results were in general agreement in bedrock depth estimation except for a long region in the middle of the dam, which assuming temporal water level variation, is an area of potential internal erosion. Higher water levels when the CCR data was collected in the spring are believed to have resulted in lower resistivities, due to the presence of water, while lower summer water levels resulted in higher resistivities for the ERI results, suggesting that fines may have been eroded out of the interior of the dam over time. This indicates that both CCR and ERI provide consistent data and demonstrates the importance of resistivity monitoring or seasonal surveys for internal erosion detection. The use of these resistivity methods also successfully detected a potential seepage path along the downstream toe of the dam where large seeps occur during large precipitation events.

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