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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...

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...

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To simplify works on restoration of the roller tracks of the main fixed-axle gates of the culverts when they are worn and to reduce expenditures, the design of the roller tracks was fundamentally changed, Instead of the embedded cast tracks, rolled plates in which removab%e forged bushings are fastened are used (Fig. 4), The operation of repair of the roller tracks amounts to replacing the worn bushings with new ones A fundamentally new scheme of automatic control of locking based on the use of noncontact logic elements was developed for the first time in the design of the Cheboksary lock. The main component in this scheme is a logic machine controlling locking, which has a number of substantial advantages compared to the relay scheme:high degree of reliability providing continuous 24-h operation during the navigation season; the logic elements composing the machine have a practically unlimited service life (guaranteed life, 12 years); high noise stability; simplicity of maintenance; low cost.The logic machine controlling locking performs the following operations: a) reception of information arriving from the dispatcher's control board and formation of a system of instructions controlling the operation of the actuating mechanisms in conformity with algorithm for the technological process of locking; b) reception and storage of information arriving from external sensors monitoring the operation of the actuating mechanism of the lock (degree of filling of the lock chambers, position of the gates, etc.); c) control and monitoring of the operation of the light signals; d) protection of the mechanisms and devices of the lock from accidents and prevention of emergency situations.The introduction of the aforementioned designs aimed at increasing the reliability and improving the operating conditions of the lock effect also a considerable saving. The plan of construction work calls for a stepped scheme of constructing the SayanoShushenskoe dam with offsetting of the downstream face with differences of heights between columns as much as 35-55 m. Construction of the dam is accompanied by filling of the reservoirs which necessitates its annual stage-by-stage sealing by grouting the joints between the columns and sections.A grouting temperature of +2-7~ is achieved by pipe cooling of the concrete.The spacing of the pipe coils is 1.5 x 1.5 m.The bulk of the works on sealing the dam, with consideration of its state of stress, should be performed in the winter--spring period during seasonal drawdown of the reservoir. Grouting works at a concrete temperature below 0~ are not permitted by the existing technological regulations.However, the design characteristics of the dam and scheme of its construction and the climatic conditions of the construction region do not make it possible to completely eliminate freezing of the concrete,The vertical and horizontal surfaces are exposed to the effect of outside air temperature for a long time, in some cases up to 2-3 years.This leads to the penetration of the frozen zone of concrete to a d...