Scientific basis of the designs of the underground structures of the Rogun hydroelectric station

Abstract

The complex of underground structures of the Rogun hydroelectric station is unique not only in Soviet but also in foreign practice of underground hydrotechnical construction.The specific features of the structures are characterized by the parameters of the hydrostation and by the natural conditions of the zone of its site [i, 2].In a geological respect the zone of the site represents a single tectonic block bounded by several faults.The seismicity of the zone of the hydrostation, as of the entire region, is rated at intensity 9.Relative displacements of the walls are occurring along the sutures of the faults -the Ionakhsh and No. 35 --at a rate of 1-2 mm/yr.It is presumed that in the case of an intensity 9 earthquake the one-time displacement along the suture of fault No. 35 can reach 10-15 cm and along the Ionakhsh fault a few tens of centimeters.A characteristic feature of the rock mass of the hydrostation zone is the presence of high tectonic compressive stresses in it. The values of the vertical stresses exceed by a factor of 1.3-2 the stresses from the overlying rock stratum; the horizontal stresses exceed the vertical by a factor of 1.4-2.3.