The concrete dam of the Krasnoyarsk hydroelectric project has a triangular profile with a vertical upstream face and an inclined downstream face with slopes of 1:0.8 (in the spillway section) and 1:0.76 (in the power station section). The dam is 124 m high. Deformation joints are spaced every 15 m; the sections are divided into columns with a lateral dimension of 11.5 m [1].The dam foundation consists of strong, jointed granite. The modulus of deformation of the rock mass, determined by subjecting a rigid plate to a vertical load, is equal to: a) sparsely jointed rock E = 1.6 X l0 s kg/cm z b) medium-jointed rock E = 0.9 X 10 s kg/cm z c) highly jointed rock E = 0.45 X 10 s kg/cm z Shear tests on "chunks" from relatively weaker fissured rocks indicated that the rock has a modulus of deformation* of (0.50-0.62) X l0 s kg/cm z.Concrete Mix. The body of the dam consists basically of concrete of the following grades: M200, B-8 (lower portion of the upstream face) and M250, Msp-300. The concretes were prepared from normal-heat cements from the Krasnoyarsk cement plant. The consumption of slag Portland cement was 230-240 kg/m s for M200 concrete and 280-310 kg/m s for M250 concrete. The Krasnoyarsk cements, manufactured in accordance with the technical specifications of the Kramoyarskgesstroi, are of the normal-heat variety as revealed by their use, yield good hydrotechnical concrete conforming to the specifications laid down by GOST 4795-67, greatly facilitate temperature regulation, and fulfiU the conditions of remaining monolithic during severe winter weather.

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It is required to regulate filling of the reservoir with consideration of the temperature field of the structure.The Sayano-Shushenskaya gravity-arch dam has been in service in the design mode since 1990. During the 16-year period of normal service, it has been repeatedly subjected to large-scale technogenic effects. The most significant of these has been repair work performed to eliminate seepage within a zone of cracking of the first column of the dam between elevations 344 and 359 m. This work was conducted in 1996 in the concrete of the thrust face in sections 19, and 21 -46 at high upper-pool levels (UPL) using "Rodur" twocomponent epoxy resins [1,2]. Injection of the loosened rock bed of the channel dam with a material of similar composition was carried out during the period from 1998 through 2003 [3]. Work on restoration of the anti-seepage properties of the upper portion of the deep grout curtain was conducted in several stages: under sections 40 -42 in 1998, sections 26 -29 in 1999, sections 30 -39 in 2000, sections 15 -25 in 2001, and under sections 43 -48 in 2002 and 2003. In each of the stages, the repair work was done in two phases: first phase -at minimum upper-pool levels; and, second phase -with the UPL close to maximum. Individual subhorizontal cracks with the greatest seepage, which were situated within the concrete of the first column between elevations 374 and 386 m (upper zone of cracking) were subjected to "medical treatment" in 2004. In 2006, work involving repair of a permeable section of the right-bank grout curtain, which was located between elevations 344 and 413 m, was begun during the stage of the reservoir's filling.Timely repair operations within the concrete of the thrust face and bed of the channel dam using non-traditional procedures and materials made it possible to achieve the following expected results:-heavy seepage through the cracked section of the thrust front between elevations 344 and 359 and 359 and 386 m has been suppressed; residual seepage flows have amounted to 5 liters/sec (1996) and 8.5 liters/sec (2004), whereas their maximum values in the periods prior to the repair had been 458 and 55 liters/sec, respectively; -the concrete in the lower section of the thrust face has been pressed in the cantilever direction, and residual additional compression has amounted to from 1 to 2 MPa; and, -seepage flow within the bed of the channel dam has been reduced from 549 (1996) to 50 liters/sec.In individual years of the repair and post-repair periods, the conditions under which the reservoir has been filled have been characterized by a large influx in different stages of the rise in the UPL, and prolonged maintenance of high levels at elevations close to the normal backwater level (NBL). In 2001 and 2004, the maximum rate of filling of the reservoir reached 1.9 m/day. After a rapid increase in hydrostatic load occurs during sudden filling of a reservoir, the temperature of the concrete in the downstream face does not have time to rise significantly. And, radial displacements...

The experience of carrying out grouting works during construction of high concrete dams attests to a substantial change in the stress state of adjacent columns under the effect of a comparatively small pressure on the surface of the joint between the columns [1]. In this connection the authors as early as the stage of working out the specifications for suppressing seepage through the stretched zone of concrete of the Sayano-Shushenskoe hydrostation dam gave special attention to possible consequences (positive and negative) of injecting grouts into seeping cracks at pressures considerably greater than those observed during grouting of the joints between columns and sections of the same Sayano-Shushenskoe dam during its construction. The firm approved to carry out the grouting works was supposed to inject comparatively viscous grouts of the "Rodur" type, as on other objects in past years, at a pressure exceeding 40 MPa at the pump outlet, which rapidly dropped on advancing along the injection path with a length of 15-20 m and at the mouth of the crack varied within 6-8 MPa with a 3 x 3-m arrangement of the holes and delivery of the polymer material through two holes. Only such a pressure made it possible to provide high-quality and continuous filling of the cracks with grout even with a small opening.During approval of the specifications specialists of the firm asserted that the effect of the grout pressure was limited to a small zone near the hole and additional opening of the cracks would not exceed the compressive strains from the unique press plate, which in cross sections with through cracks usually did not exceed 1 mm.Different regularities of additional opening of cracks that partially disturbed continuity of a cross section about 80 m high to a depth of 15-17 m ought to be expected in the particular case of grouting. The more so as grouting was to be done at upper pool levels (UPLs) close to the normal pool level (NPL), when the cracks without additional interference were in an equilibrium state.In the first years of normal operation it was established during drilling of exploratory holes and inspecting the walls by means of TV cameras that cracks were prevalent in the mass in the form of numerous small disturbance of the solidity of the concrete in zones 1.5-5.6 m high. Exploratory drilling before the start of grouting in 1996 showed the presence in each section of one to three zones with several cracks with a comparatively small opening. According to the readings of long-base deformometers, the openings of the cracks immediately before the start of industrial grouting at an UPL close to elevation 540 m were from 0.33 to 0.98 mm. At the dead storage level all cracks were practically closed. A plan was drawn up for grouting 40 zones in 24 sections to fill the main and small, intensely seeping cracks with grout into the depths of the mass. During grouting one could not assume penetration of cracks into the depths of the mass of the dam in connection with the fact that calculations established a zone of tensi...

Field observations of the 40-year-old dam suggest good quality of construction-assembly work and professional operation of the power plant.The concrete dam of the Krasnoyarsk hydroproject is a gravity structue with discharge chambers 4 -6 m wide in the base, a vertical thrust face, a downstream face inclined at 1:0.76 in the powerhouse section, and at 1:0.8 in the remaining section of the dam (Fig. 1). It has a maximum constructed height of 128 m, and length of 1072.5 m along the crest. The body of the dam is cut into sections 15 m wide and columns 11.5 m long. The expansions joints between the sections are sealed by keys formed from metallic sheets and grouting of a portion of area of the joint in lieu of the asphaltic keys normally employed. The granite rock bed beneath the lower surface of a heavily grouted curtain extends to a depth of up to 60 m. Weep holes are situated 5 -7 m from the upstream face, and are continued for 30 -40 m into the rock bed.The first generating sets at the plant were started in November 1967, and the hydroproject was placed in continuous service in 1972. In this paper, it is our intention to trace how the basic diagnostic indicators of the dam's condition have changed after 40 years of service.Information on the average strength characteristics of the basic grades of concrete, which were obtained during construction, and from recent measurements is presented in Table 1.A negligible decrease in strength has occurred on the outer faces of the dam in a layer with a thickness of up to 100 mm. The concrete in the split abutment, separate bulkheads of the bottom (construction) discharges, and the slab stabilizing the right bank in the immediate vicinity of the discharge section of the draft tubes of the generating sets has been largely subject to deterioration to a depth of up to 200 mm in the zone of variable water level on the downstream face.Use of special medium-thermite cements from the Krasnoyarsk Cement Plant, which had been developed for waterdevelopment works in Siberia, has contributed heavily to the