When the United States Army Corps of Engineers (USACE) Nashville District designed and constructed a new lock at the Kentucky Lake Lock and Dam site, US 62/641 had to be relocated downstream of the dam. The relocation required 1.7 miles of new roadway and a new 10-span, 3,000-foot-long bridge over the swift waters of the Tennessee River. The project also required 12,000 feet of approach embankment. We were hired to develop and oversee geotechnical explorations for roadway and structures with special consideration taken for the karst limestone conditions in the project area. Significant monitoring and instrumentation for deep drilled shaft construction was incorporated using sonar calipering methods, video inspection of underwater surfaces, and cross-hole sonic logging.
Large settlements of foundation soils from the new embankment construction above the existing dam toe drains presented a challenge. In order to reduce settlements to acceptable weight limits, we designed a lightweight fill embankment consisting of expanded polystyrene (EPS) geofoam blocks instead of engineered fill soils. This was the first use of geofoam in the state of Kentucky and the design received an award.