Earthquake Resistance of Sloping Core Dams

Models may be used for studying various aspects of the earthquake resistance of rock or gravel fill dams with sloping clay cores. Similitude requirements must be satisfied in the construction of model dams, and consideration must be given to rate of loading and pore-water pressure effects. A test program, in which models of a proposed dam were subjected to a simulated earthquake, shows that, although the simulated "quake" was conservative, it did not produce a catastrophic failure of the models. Its major effect was to cause some settlement of the upper section of the upstream slope and a slight heaving of the lower section of the slope. An analysis compares the ground acceleration at which permanent deformations began to occur with the computed ground acceleration required to induce incipient failure using a conventional stability analysis. Substantial economy in the design of sloping core dams in seismically active regions can be achieved by accepting minor deformations and slumping of the dam during a major earthquake.