Toktogul hydroelectric station

Kuz'min, K. K.; Berezinskii, S. A.

doi:10.1007/bf02377376

Cited by 8 publications

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“…The experience gained during the extended service of these tunnels under different conditions, extending over six to severr years, permitted their operational features to be defined and recommendations to be formulated for more accurately defining design decisions for similar high capacity diversion tunnels.Descriptions of the diversion tunnels at the above-mentioned hydropower schemes are given elsewhere [1,2,3]. Presented in Tables 1 and 2 are, respectively, their principal engineering features and operational factors.…”

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confidence: 99%

Improvements in diversion tunnel design

Kuperman¹,

Mostkov²,

Ilyushin³

et al. 1975

Hydrotechnical Construction

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The 1960's saw the beginning of construction of several high-head hydroelectric schemes in the Central Asian republics of the Soviet Union, viz., Charvak, Nurek, and ToktognL For river diversion during the construction of these hydroelectric schemes, large cross section tunnels were used, which operated unt.il 1972 to 1974. The experience gained during the extended service of these tunnels under different conditions, extending over six to severr years, permitted their operational features to be defined and recommendations to be formulated for more accurately defining design decisions for similar high capacity diversion tunnels.Descriptions of the diversion tunnels at the above-mentioned hydropower schemes are given elsewhere [1,2,3]. Presented in Tables 1 and 2 are, respectively, their principal engineering features and operational factors.Stage I and II tunnels of the Nurek scheme and the Toktogul tunnel were designed to pass only the construction floods. The Charvak diversion tunnel, after remodeling, was placed in permanent service. The service spillway is connected to it 480 m from its upstream portal.All the tunnels were designed to operate under free-and pressure-flow conditions. The Nurek I and Toktogul tunnels are unregulated; they were designed to operate only in the first stage of construction-flood diversion, before reservoir filling. The leaf gates installed in the Toktogul and Nurek I tunnels were designed for single closure for their isolation. The Charvak and Nurek II tunnels were used to pass the construction floods during both stages. During the second stage, i.e., reservoir filling for the commissioning and operation of the Stage I turbogenerator units, the flow through the Charvak and Nurek II turmels was regulated by radial (sector) gates. These gates were desigr~ed for a maximum head of 80 and 110 m, respectively.The Toktognl and Nurek tunnels have a flat-bedded cross section, the Charvak has a circular profile. The reinforced-concrete linings of all the tunnels were designed to prevent cracking.In connection with the high velocities in the tunnels (Table 2), certain design standard criteria were developed for the lining surfaces. However, even during the first stage of construction-flood diversion, a nonuniform erosion of the linings occurred, which resulted in local irregularities with dimensions significantly exceeding the design limits. This indicates the necessity for a secondary treatment of the concrete lining surfaces, in order to prevent cavitation damage during subsequent stages of tunnel operation. It should be noted that it was the first

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mentioning

confidence: 99%

Improvements in diversion tunnel design

Kuperman¹,

Mostkov²,

Ilyushin³

et al. 1975

Hydrotechnical Construction

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2015

Seismic Loads

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Condition of the concrete dam of the Toktogul hydroelectric station according to on-site observation data

Berezinskii¹,

Enikeev²,

Maksimov³

et al. 1985

Hydrotechnical Construction

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To increase the overhaul time of the turbine bearings at the Kremenchug hydrostation the following measures were taken:i. The rotors of the units were balanced by placing weights of 450-800 kg on the rotor rim. Balancing was carried out by the method and under the supervision of workers of the I. I. Polzynov Central Boiler and Turbine Research and Development Institute with consideration ofmechanical, electrical, and hydraulic imbalance.2. The ellipticity of the turbine bearings was determined and eliminated. Ellipticity was determined by measuring the gaps between the rubberized bushings and turbine shaft with the thrust bearing raised. The gaps were measured by a special gauge witha vernier. Three measurements at the trailing and leading edges and in the center (a, b, c) were taken opposite each segment.The measurement results are given in Table i. A further determination of ellipticity was carried out by the graphic method with the use of the data of column 6 of Table i. With the use of an arbitrary circle at a scale of 10:1 (or any other scale) the values of the deviations from the circle are plotted with the use of the data in column 6 of Table i. A circle is inscribed in the figure obtained and the final values of the deviation from a circle (ellipticity) of individual segments of the bearings in millimeters are determined.Individual shims are installed under segments having deviations from a circle of more than 0.3 mm to eliminate ellipticity. In addition to this, shims of the same thickness are installed under all segments (including under the segments with individual shims) in accordance with the data of "rocking" or play of the shaft before repair. Turbine bearings with elimination of ellipticity last the overhaul period with allowable values of play of the shaft.The accomplishment of the indicatedmeasures considerably increased the operational reliability of the bearings of the units of the Kremenchug hydrostation.The concrete dam of the Toktogul hydroelectric station, constructed in a narrow canyon of the Naryn River, is a massive structure consisting of a central and six side sections (three on each bank). The total height of the\dam is 215 m with a base width along the flow of 173 m.Thick-layered, quite strong marmorized limestones with widespread wall and bottom release joints are the foundation of the dam. A front grout curtain and drainage in the foundation and canyon walls are the cutoff measures.The characteristic design features of the dam are the absence of cuts into the canyon walls, the use of an additional surcharge by water, and the presence of deformation joints between sections in the shape of a fan, which made it possible to direct the main load to the foundation of the structure and to provide independent deformation of each section [i, 2].The dam was constructed by the layer-by-layer method with sectioning into concreting blocks measuring 60 x 32 m in plan and 0.5-1 m high [3]. Systematic filling of the reservoir began in August 1977. By mid-1980 the upper pool level reached the maxi...

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Toktogul hydroelectric station

Cited by 8 publications

References 0 publications

Improvements in diversion tunnel design

Improvements in diversion tunnel design

References

Condition of the concrete dam of the Toktogul hydroelectric station according to on-site observation data

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