Impact of dam site configuration on 3D stress-strain state of concrete faced rockfill dam

Hydraulic engineering

The article deals with the results of numerical modeling of the 3D stress-strain state (SSS) of a 100 m high dam with reinforced concrete face. It is shown that at the location of the dam in a gorge of any shape, the reinforced concrete face is compressed in the direction from one side to the other and in the direction along the slope it may have tensile stresses. The formation of tensile stresses in the face is caused by the emergence of tensile forces at the displacement of rockfill as well as by bending deformations. The face bend contributes to the most probable formation of tension on the downstream face. In all site alternatives the perimetral joint opens. Construction sequence and dam loading have a great effect on the face SSS formation. During the dam construction in 2 stages the face SSS turns to be more favorable than when the dam is constructed in 1 stage: face deflections, tensile and bending forces in it decrease, but the level of compression from one side to the other increases. However, during the dam construction in 2 stages the first-stage face upper part will suffer unfavorable bending deformations caused by non–uniform settlements of the rockfill. Due to the aforementioned reasons, very high rockfill dams with a reinforced concrete face (150 m and higher) may have extremely unfavorable SSS. By the results of numerical modeling, twice as much increase in the dam height led to 3.5 times as much the growth of displacements and twice as much the growth of stresses in the face. In the faces of very high dams there may appear considerable tensile and compressive stresses, which may cause concrete structural failure. Very high dams should be constructed in several stages in order to improve reliability of reinforced concrete face performance.