Renovating an Earth Dam that Predates the Civil War
Buckeye Lake Dam is a state-owned structure located within Buckeye Lake State Parkland. This Class I high-hazard dam was constructed between 1825 to 1832 as an earthen embankment and measures approximately 4.1 miles long and supports recreational uses such as fishing and boating.
In March 2015, U.S. Army Corps of Engineers (USACE) released an alarming report detailing unacceptable deficiencies in the dam, and the damage and potential loss of life that could result from catastrophic failure. Findings were excessive deterioration and long-term seepage through the earthen embankment, multiple excavations into the downstream slope, and the inability of safety inspectors to examine areas of the dam hidden by structures.
Structural integrity of dam had been significantly weakened by man-made defects (ie, homes and other structures sunk into the dam embankment). Portions of the dam have been dug away to accommodate pools, patios, utilities and drainage systems. Cracks, depressions and trees have taken root in the dam, adversely affecting the dam’s structural integrity increasing the possibility for failure.
Approximately 3,000 people live within the projected dam-failure inundation zone. Failure of the dam would result in the loss or damage to 2,100 homes as well as businesses, public safety facilities, a healthcare facility and a wastewater treatment plant.
Phase I activities included the construction of the Embankment Stability Berm (berm) and the seepage cutoff wall. Phase 1 structural risk reduction measures completed in May 2016 included placement of a 30 foot wide embankment stability berm and a nearly 43 foot deep soil mix seepage cutoff wall along the entire 4.1 mile length of the dam. Balter’s role occurred during Phase II.
Phase II will consist of continued soil mixing to support the cutoff wall and a landscaped cap that will include an asphalt access path for use by the public on top of the new dam and a sidewalk for local access.
The scope of our work includes verification coring of the cutoff wall in order to evaluate the suitability of the Contractors soil mixing operation. The coring operation, performed after a designated curing period, will consist of the use of a PQ3 size bit and a triple tube wireline core barrel to obtain a continuous sample of the weakly cemented materials through mud rotary methods. Ultimately the core is obtained and extracted for documentation and compressive strength testing.
Based on the findings of the verification cores as well as their in-situ conditions, the borehole may be flushed clean for the purpose of video logging. If necessary, a Digital Optical Televiewer camera capable of recording a 360 degree image will be used to scan the borehole to further identify the quality of the soil mixing operation.
Finally, permeability tests consisting of falling head tests will be performed on boreholes.