Rock Anchor Field Study at Bluestone Dam

Bluestone Dam is located on the New River in the Kanawha River Basin, at Hinton, West Virginia. The dam is a concrete gravity structure approximately 170 feet high and 2,000 feet long that began operation as a flood control structure in 1949. It is owned and operated by the Army Corps of Engineers Huntington District, and controls a watershed area of roughly 4,600 square miles.
The dam has a hydrologic deficiency under the revised project Probable Maximum Flood (PMF), which will overtop the structure by approximately 7 feet. Stability analyses of the structure and foundation have shown that there is danger of a deep-seated sliding failure occurring at pool levels approaching the top of the dam. Consequently, a significant improvement in the stability of the structure is required to bring it into compliance with federal guidelines. This will be accomplished by a two-phase Dam Safety Assurance (DSA) construction effort.
Phase I of the DSA project is currently underway, and includes the construction of a mass concrete thrust block at the toe of the non-overflow portion of the dam. The six penstocks will be extended through this thrust block and controlled by sacrificial bulkheads that can be opened in the event of a severe storm. Phase II of the project will include downstream scour protection, new and modified training walls, a gate closure for the adjacent state highway, a parapet wall to prevent overtopping, and numerous large rock anchors to apply stabilizing force to the dam.
This paper describes a field study performed by Fuller, Mossbarger, Scott, and May Engineers Inc. (FMSM) for the U.S. Army Corps of Engineers, Huntington District to investigate issues relating to the design, construction, and performance of post-tensioned rock anchors.