Extreme Dam Repair FEATURE ARTICLE Men at work at Wolf Creek Dam Sensing and measurement technologies are playing a significant role in the current $594 million rehabilitation of the Wolf Creek Dam in south-central Kentucky. Using sophisticated monitoring and control systems, crews are drilling 1.3 m (50 in) diameter piles as deep as 84 m (275 ft) as they construct a 1,201 m (3,940 ft) long secant wall concrete barrier along the spine of the 60-year-old earthen embankment. The project began in 2008, and the owners expect it to be completed in 2014. Despite its unprecedented parameters, no production rework has been required to date. The U.S Army Corps of Engineers originally constructed the Wolf Creek Dam, completing it in 1952 and creating the 162.5 km (101mi) long Lake Cumberland. The largest man-made reservoir east of the Mississippi River and the ninth largest in the U.S., Lake Cumberland annually attracts more than four million visitors. In early 2005, seepage concerns prompted the Corps to relieve pressure on the dam by lowering the water level by 12 m (40 ft). The purpose of the AUTHORS current remediation project is to allow the Corps to safely raise the water level once again, reestablishing the dam’s utility in flood control and power generation as well as enhancing its recreational use. Ongoing Seepage The dam has had seepage problems since its earliest days. Constructed on karstic limestone, much of the dam’s foundation deteriorated over the years through solutioning of the rock. The resulting base is far from watertight, and has periodically raised serious dam safety concerns. The Corps undertook an emergency grout ing program in 1968, and constructed a concrete diaphragm wall, completed in 1979. During the 1960s, the agency had assembled a panel of global experts who recommended constructing a full length cut-off wall to address seepage at the Wolf Creek Dam. Due to the difficulty (and expense) of constructing such a wall and the limits of technology at that time, the Corps decided only the central two- thirds of the dam length required the cut- off wall. Although the 1979 diaphragm wall performed well for years, it did not stop the seepage through the rock. In 2004, evidence of increased seepage surfaced, and in 2006 Wolf Creek Dam was at the top of the Corps of Engineers’ inventory of dams in need of remediation, based on analysis of life risk combined with economic risk if the dam were to fail. As a result, the Corps launched the current Wolf Creek Dam Major Rehabilitation Project in 2006 with the goal of constructing a concrete barrier cut-off wall along the full length of the earthen portion of the dam. The Corps awarded the barrier wall contract to Treviicos-Soletanche Joint Venture (TSJV) based on its best-value proposal. The joint venture is led by Boston-based Treviicos, the North America subsidiary of Trevi, headquartered in Italy. Soletanche Construction, a subsidiary of Soletanche-Bachy of France, is the other partner. Both companies brought significant experience and expertise to the project and, with the Corps, developed an innovative plan for constructing the barrier wall. In October 2008, the Corps issued the notice to proceed. Stefano Valagussa, president and CEO, Treviicos; Fabio Santillan, Joint Venture project manager, Treviicos; and Vincent Jue, vice president, Soilmec North America 44 • DEEP FOUNDATIONS • MAR/APR 2013
