Geotechnical Engineering
Catawba River Embankment Dams Seismic Stability Analyses
Duke Energy owns and operates 20 hydroelectric stations in North Carolina and
South Carolina. Several stations include embankment dams constructed in the
early 1900s with dumped fill or semi-hydraulic fill methods.
Provide all engineering services to ensure that six embankment dams, ranging in
height from 75 feet to over 160 feet, meet FERC stability criteria for the
design earthquake load case.
Devine Tarbell & Associates, Inc.’s (DTA) staff reviewed available documents and
photographs to obtain information on construction methods and construction
quality. Extensive geotechnical site investigations were conducted to assess
soil stratigraphy, in-place densities, in-place shear strength and seismic
properties, and to obtain samples for laboratory testing. Piezometers and a
monitoring well were installed to measure pore water pressures. A comprehensive
geotechnical laboratory test program was implemented to determine soil
properties, and seismic stability analyses were performed. These seismic
analyses included static stress analyses using FEADAM84, one-dimensional dynamic
response analyses using SHAKE91, and two-dimensional dynamic finite element
analyses using QUAD4M.
Geotechnical field and laboratory testing were completed for all six
embankments. Detailed reports summarizing the work and proposing analysis design
parameters were prepared and submitted to FERC for review.