HE IMPORTANCE OF SITE INVESTIGATIONS FOR THE SAFETY OF NUCLEAR POWER PLANTS DURING OPERATION.

For assuring the stability of important buildings (nuclear power plants) during strong earthquakes, the soil strata under these buildings should not get deformed during the events. In the paper will be analyzed the nonlinear behavior of soil layers during strong earthquakes. As follows from the soil dynamics experiments, shear modulus G and damping D become functions of strain level γ and nonlinear behavior could take place. Further, changes could appear in the mechanical properties of the soil layers, expressed by their dynamic response during strong seismic movements. There will be presented researches and tests done at National Institute of R-D for Earth Physics. [ABSTRACT FROM AUTHOR]