Subsurface and geocryological conditions impacting the construction of power structures in northeast USSR are reviewed. The sites are characterized by nonhomogeneous geological structure, cryogenic texture in the foundation rock or soil, and sharp differences in temperature conditions of the rock or soil within the foundation area. Large temperature variation is exhibited by the presence of talik zones composed of highly permeable rock confined by ice-saturated, ice-rich ground. A. significant loss of the bearing capacity and an increase in permeability of rock or soil that would endanger the stability of the structures were predicted upon thawing. However, geocryological factors were of paramount importance in adopting design solutions.
Examples of design solutions and modifications during construction included: (l) the foundation rock or soil was kept frozen; (2) talik zones, both natural or those formed during the construction, were frozen; (3) impervious elements of the storage dams were installed using refri gerating units of different types.