Seismic stability of the Toktogul dam

Abstract

1. Investigations of oscillations of the Naryn River canyon at the site of the Toktogul hydrodevelopment during passage of seismic waves presented to us a detailed picture of the movement of the canyon flanks, permitting a reduction in the design accelerations of the flanks and refinement of the seismic load on the dam. 2. Investigations of the shear stability of the Toktogul dam showed that for the adopted seismic load the dam is highly stable. 3. Theoretical and model investigations of the stresses and strains in the dam for different directions of approach of the seismic wave showed that the intensity of the dynamic tensile stresses in the upstream face does not exceed the static compressive stresses. Thus, tensile stresses do not occur on the upstream face at the given level of the seismic load. 4. Investigations of the character and form of failure of dam models under a seismic load revealed considerable strength reserves of the dam, which permit partial or complete elimination of the placement of indentations in the concrete on the downstream face of the dam.