Results of on-site observations in the contact zone of the dam and foundation of the Sayano-Shushenskoe hydroelectric station

Abstract

1. The most substantial and sharp changes in the state of the rock-concrete contact appeared beginning in 1985 after reaching 76% of the design hydrostatic load. 2. Opening of the rock-concrete contact is distinguished by a nonuniform rate of change with time and nonuniform distribution of the amplitude of opening along the front of the dam, which reflects the complex interaction the dam with the foundation and effect of inhomogeneity of the foundation and different technological conditions of placing the contact concrete. 3. Opening of the rock-concrete contact is accompanied by substantial changes in stresses and strains in the rock and concrete of the contact zone and in the piezometric heads in the foundation, reflecting structural changes in it during interaction of the dam with the foundation. 4. In addition to the effect, which occurs for all types of concrete dams on a rock foundation, of technological factors and design differences of individual parts of the dam on the behavior of the contact zone of the foundation and concrete of the Sayano-Shushenskoe dam, also noted are such features as active opening of the rock-concrete contact over the entire length of the channel part of the foundation, presence of signs of “hanging” of the arch on the first columns on the banks, and a special stress state of the concrete in the lower part of the upstream face, which can be a reflection of the design features of the gravity-arch dam.