On-slte investigations of seepage in the foundations of dams are one of the most important methods of monitoring the state of the foundation and behavior of the structures. On the basis of the character of seepage and its development during filling of the reservoir one can Judge the permeability of the./rocks, presence of seepage-defomatlon phenomena, effectlveness of the underground contour and cutoff and stability of their operation, and state of stress and strain and its change with time. On-slte investigations of seepage are especially necessary for hlgh-head dams, in the foundations of which large stresses occur and nonuniform deformations are possible.The foundation for the dam of the Ingurl hydroelectric station [I] is composed of llmestones, dolomltlzed limestones, and dolomites. The rocks are characterized by increased or severe Jolnti~.The Joints, as a rule, are filled with clay, loam, and grus. Within the active seepage zone there are a number of large tectonic fractures (Nos. 8, 15, 15a, 16, 19,(51)(52)(53) 616, etc.) and a rlght-bank fault. A number of fractures (Nos. 8, 12, 15, 15, 19, and certain others) have dense clay filling material and a developed system of pinnate fractures. The permeability of the rocks is characterized by a specific inflow to wells on the right bank within 0.15-1.88 llters/min.m s and on the left bank 0.11-0.4 llter/min.m 2. The permeability of the rocks decreases with depth, but it was not possible to reach impervious zones during drilllng of exploratory wells to a depth of 120-150 m.The flow interruption in the dam foundation includes grouting to a depth of 15-20 m, and to a depth to 140 m and length up to 200 m in the banks, and a system of channel end canyon-wall drain wells. The largest fractures, Nos. 8, 16, and 19, and part of the leftbank fault adjacent to the dam are being excavated by the mining method and sealed with concrete. There are six levels of grouting, drainage, and access tunnels in the dam foundation end canyon walls for conducting drilling operations. 0n-slte investigations and observations in the dam foundation were begun by the State All-Unlon Trust for the Stabilization of Foundations and Structures (Gidrospetsproekt) in 1971 and have been carried out continuously since. These investlgatlons can be divided into three periods according to their tasks and nature: the first included excavation of the foundation pit and underground workings of the sixth horizon, the second flooding of the pit, and the third fill~n S the reservoir.The on-slte investigations of seepage durln8 the period of excavation of the underground workings and pumping out the foundation pit were carried out for the purpose of supplementing and refining ~he data from surveys and detailed studies of the permeability of the foundation rocks, using the created conditions of seepage into the pit (head up to 38 m) and variations of the water level in the river in front of the cofferdams. The tasks of the invest~ations included a determination of zones of concentrated and increased seepage...
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...
Rendering the construction joints monolithic is particularly important in the design and erection of high concrete dams, especially arch dams when the strength characteristics of the concrete are exploited to the greatest extent. In Soviet practice the pipe system of grouting is usually employed for grouting the construction joints.The piping is laid over the whole area of the joint, divided into grouting maps and joined up with the cavity of the joint by cutlets of various design (point, line, etc.). To improve the conditions of filling the joint with grout, a dentation is worked into the upper part of the map for leacing off the air.A 20:0.4 water-cement grout is used [1] for rendering dams monolithic. Grouts with a water-cement ratio of approximately three and over, approach the properties of viscous, Newton type liquids,while with a ratio less than three they behave like viscous-plastic (Bingham) liquids.The flow conditions of Newton and Bingham liquids in the pipes of the grouting system and the joint may be respectively laminar, transitional or turbulent, or structural, transitional or turbulent. At different parts of the pipe system and in different zones of the joint different flow conditions may be observed.The study of the hydraulic map of joint grouting is carried on along different lines and by different methods. This paper studies the flow and pressure distribution during the grouting of joints, employing the method of electric hydrodynamic analogies.In some cases it is possible to study laminar flow of a viscous (Newton) liquid by the electric-hydrodynamic analogies method. The results set out below may therefore be valid only for the injection into the grouted joint of a grout with a high-water-cement ratio (W/C > 3), when the grout will in essence be a Newton liquid. Investigations using the electric-hydrodynamic analogies method, disregarding hydraulic resistance in the feed system and outlets, were carried out during 1965 [2]. Similar work was carried out for the purpose of more closely simulating actual conditions, taking into account the hydraulic resistance in the pipes and outlets.* Lamina flow of the Newton liquid was assumed in the joint and in the pipes of the injection system. Electrically-conducting paper was used for the model of/he grouting system and joint. At the positions of the outlets, strips of electrically conducting paper simulating the hydraulic resistance in the pipes were connected with a sheet of electrically conducting paper simulating the hydraulic resistance of the joint.The width and resistivigy of the strips were taken in accordance with the equation where b 1 and Pl, b2 and Pz are respectively the width of the tape and the resistivity of the electrically-conducting paper, simulating the hydraulic resistance in pipes with diameter d i and d z.In order to find the relationship between the joint opening and the resistivity of the sheet of electxicallyconducting paper simulating its hydraulic resistance, use was made of the equation *See Gidrospetxsproekt report "Investi...
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