Stability Analyses of Smith Mountain and Leesville Dams

Abstract Only - The Smith Mountain Dam, located on the Roanoke River in Virginia, is a double curvature concrete arch dam with a maximum height of 237 feet and overall length of 816 feet. The reinforced concrete arch is 9.5 feet thick at the crest and 35 feet thick at the base. The upper contact with the foundation rock is facilitated through the use of thrust blocks on both abutments.
The stability analysis of the dam considered construction sequence, temperature variation, spillway level and probable maximum flood, and earthquake ground motion loadings. The main analysis of the dam was carried out through the use of the SAP2000 finite element program. However, auxiliary analyses were performed through the use of the University of California program EACD-3D-96. EACD considers the effect of dam­water interaction, water compressibility, reservoir boundary absorption, as well as the flexibility of the foundation rock. All earthquake analyses were based on site-specific ground acceleration time-history, which was developed specifically for the evaluation. The possibility of contraction joint separation under seismic excitation was considered in the analysis. Special analysis was also required for one of the thrust block abutments, which bears on partially fractured rock. The findings of the analyses will be presented, together with discussion of the uses and limitations of the various programs used.
The Leesville Dam is a concrete gravity dam, which is located 15 miles downstream from the Smith Mountain Dam. This dam is approximately 980 feet in length and consists of three contiguous straight-line sections. The largest block of the dam is approximately 90 feet in height, 9 feet thick at the crest and 63 feet thick at the base. The primary analysis of the Leesville Dam was carried out through the use of the EAGD-SLIDE program, developed at the University of California at Berkeley. Auxiliary analyses were performed on the EACD-3D-96 program, as well as Anatech's CO-DAM program. This dam was analyzed for similar loading conditions as used for the Smith Mountain Dam.
Note. These services are currently in progress, but will be completed well in advance of the Conference. Therefore, this abstract cannot presently discuss findings and their impacts. These issues will be included in the Conference paper.