Power Technology and Engineering (formerly Hydrotechnical Construction)

Orekhov, V.; Babayan, A.; Marchuk, M.

doi: 10.1007/BF01545380pmid: N/A

1. The results of combined static and seepage calculations of the powerhouse section of the Bratsk dam shows a satisfactory agreement with data of on-site observations with respect to the length of opening of the contact joint and diagram of seepage heads in the contact zone, stresses and displacements of the structure, opening of the column joints, and seepage discharges in the foundation. The closest agreement of the calculated and on-site data was obtained with consideration of stages of constructing the dam in the calculations, which corresponds to the real working conditions of the structure. 2. The agreement of the results of the calculations and on-site data confirm the possibility of mathematical modeling of the behavior of real structures on rock foundations with consideration of the complex set of external factors: stages of construction, presence of joints and cracks in the dam and foundation, seepage along fractures, contact joint, and in entire blocks of the rock, elastoplastic behavior of the material, and temperature effects. 3. Calculations of the SSS, strength, and stability of the Bratsk dam with consideration of the real strength and deformation properties of the materials show that the lightweight powerhouse sections are in a satisfactory operating state. The minimum value of the coefficient of stability against shear for the examined calculated cases is 2.21. 4. The picture of the seepage regime of the dam foundation confirms the data of on-site observations of the high effectiveness of the drainage system and possibility of eliminating a grout curtain in low-permeability rock masses. In this case, the diagram of the seepage heads over the base of the structure differs from the standard one. 5. Opening of the contact joint and decompression of the foundation under the upstream face of concrete dams leads to worsening of the scheme of the static behavior of the structure and requires adequate reflection in the practice of designing these engineering structures.

Belyaev, S.; Ishangaliev, T.; Kariev, D.; Kuklin, D.

doi: 10.1007/BF01545381pmid: N/A

The installation of a radial cascade with five blades and a guide cylinder (variant 1.3) and cascade with transverse ribs and deflectors (1.6 and 1.7) increases the total hydraulic resistance coefficient, but at the same time help to eliminate nonuniformity of the flow in front of the Impeller and to reduce the input power by 10% in the small-delivery zone and by 2.5–3% in the optimal operating zone of the MUPS while keeping sufficiently high efficiency values.

Malakhanov, V.; Gassan, Ebrakhim

doi: 10.1007/BF01545382pmid: N/A

1. The presence of local resistances on the path of pressure conduits and outlets leads to nonuniform flow of the water due to additional turbulence of the flow and, as a consequence of this, to a shift of the boundary of the similarity zone toward the zone of smaller Reynolds numbers, which makes possible a well-founded reduction of the scales of models according to formula (1). In this case a determination of the boundary Reynolds number Reb with the use of the equivalent roughness method can be carried out by Nikuradze's, Al'tshul's, or Prudovskii's formulas with substitution of the values of the relative equivalent roughness in them. However, before obtaining broader experimental data on determining the effect of various local resistances on Reb in nonuniform pressure flows, it is necessary to use formula (7) as the one giving more cautious results. 2. As shown by the calculations for determining the scales of models of sag pipes constructed in our country, disregard of the effect of local resistances in the form of bends, joints, grooves, i.e., determination of the boundary Reynolds numbers for flows in sag pipes as for uniform flows (Nikuradze's, Levi's, Al'tshul's, and Prudovskii's formulas) results in that the models of the sag pipes cannot be made in scales smaller than 1∶2–1∶5. Determination of Reb by formulas (6) and (7) with consideration of the effect of local resistances by the equivalent roughness method enables a well-founded reduction of the scales of the models to 1∶20–1∶50.

Panteleev, V.; Sobol', S.; Ogarkov, A.

doi: 10.1007/BF01545383pmid: N/A

At the given stage the described suggestion has been substantiated by calculation, and therefore as the next stage it is necessary to conduct a full-scale experiment, which will make it possible to work out practical recommendations on using this suggestion when constructing earth dams and various embankments, when conducting maintenance and reconstruction works on industrial waste dumps, etc.

Belonozhko, V.; Kagan, M.

doi: 10.1007/BF01545384pmid: N/A

The strength of concrete was investigated. It was found that in the case of charging individual concrete components into TMs mounted on the chassis of KrAZ and KamAZ trucks, high-grade concrete cannot always be prepared with such a technological scheme.

Kagan, M.; Belonozhko, V.

doi: 10.1007/BF01545385pmid: N/A

A comparison was made of the water absorption of two fiber-reinforced concrete blocks with different geometric parameters of the fibers. It was found that in the case of using thin fibers d=0.5 mm (block No. 2), the water absorption by weight was less and it was distributed more uniformly over the entire length than in the case of using fibers with d=1.5 mm (block No. 1). A dependence of the coefficient of variation on Ww was established (a decrease of Ww causes a decrease of Cv and vice versa). This was displayed especially clearly in block No. 1 (thick fibers) and less so in block No. 2. Furthermore, it was found that the addition of thin fibers directly into the concrete mixer (into the mixed concrete) leads to their clumping and ultimately to the occurrence of “hedgehogs” in the concrete and to worsening of Ww. Clumping of fibers occurs little, if at all, when thick fibers are added to the concrete mixer. Precisely the addition of fibers to the concrete mix is one of the most complex problems in the given area of construction.

Gusev, V.

doi: 10.1007/BF01545386pmid: N/A

1. Additional moistening of soils by irrigation increases the rate of infiltration and overland runoff. Under certain conditions disturbance of the natural water regime of a drainage basin or its part leads to secondary salinization and waterlogging of the territory and to intensification of the erosion process. 2. Deepening and straightening of the channels of water intakes and cutting of catch canals lower the natural base of drainage, increase the zone of depression of groundwaters and their flow to intakes, and disturb the historically established hydrological equilibrium in the drainage basin being drained and adjacent ones. 3. Without providing environmental protection measures, land reclamation is accompanied frequently by intensification of the migration of suspended and water-soluble soil-fertility elements to water objects, which leads to pollution of water sources. 4. The main measures for protecting water and soil resources in land reclamation are a determination of the boundary of drainage and irrigation ameliorations and zone of nonintervention, standardization of the areas of drainage and irrigation in river basins, calculation of the maximum allowable withdrawal of water from the river runoff for irrigation, additional water regulation, construction of water-recycling systems, and implementation of erosion-control measures.

Kuz'min, S.; Mozhevitinov, A.

doi: 10.1007/BF01545387pmid: N/A

Mukhamedov, A.

doi: 10.1007/BF01545388pmid: N/A

Akhmedov, T.; Spitsyn, L.

doi: 10.1007/BF01545389pmid: N/A