Effect of rock masses surrounding concrete dams on their behavior

Abstract

1. Geodynamic movements of surrounding rock masses can affect the behavior of arch dams. Creep movements of slopes can cause a change in the former scheme of static behavior of a dam, being expressed in a different reaction to the previous combination of acting loads. 2. The effect of seismotectonic activity during the earthquake precursory period is manifested in the form of fluctuations of the on-site data: strain-gauge, geodetic, and piezometric. The location of the detector that recorded fluctuations and values of these fluctuations characterize the temporal change in the scheme of static behavior of the dam reacting to deformation of the blocks and slabs of the surrounding masses. 3. For concrete dams constructed in narrow mountain canyons, it is necessary to conduct on-site observations according to a special program compiled on the basis of an analysis of the state of the dam in the first years of operation to detect geodynamic and seismotectonic activity. These observations should be informative for: Determination of the effect of the surrounding rock masses on the state of the dam; study of the role of technogenic factors in natural processes; selection of earthquake precursors; determination of the seismic stability of the dam. 4. On all dams constructed in mountain canyons it is necessary to make a retrospective analysis of the on-site data to determine the interrelations in the reservoir-dam-surrounding rock mass system. 5. The data of on-site observations of the responses of a dam to geodynamic and seismotectonic processes can be used by basic science for gaining knowledge about the earth's crust.