ALBERT

Notes: Conclusions 1. The use of poured concrete with plasticizer GKZh-94 in difficultly accessible parts of structures, such as the “plug” of dewatering outlets, is effective with respect to the conditions of delivering the concrete to the placement site and considerably reduces labor expenditures on its compaction. 2. The overconsumption of cement for poured concrete is compensated by the reduction of labor expenditures on delivering the concrete mix to the placement site and its compaction. 3. Under conditions of Siberian rivers with large diversion discharges, it is necessary to have several sets of mechanisms and equipment for closing the outlets — hydraulic hoists, cantilevers, portals, rods, guard gates — for increasing the rate of construction and eliminating downtimes in unforeseen or emergency situations.

Notes: Conclusion The preceding calculation schemes and corresponding numerical results show that the available information on the properties of soil materials and methods of calculation (solutions of static and eigenvalue problems for a linearly elastic medium on the basis of the FEM, interaction of an oscillator with a half-plane, etc.) permit evaluating the seismic stability of earth dams within the scope of the standard method with approximate consideration of the most characteristic features for such structures (nonlinear deformability and saturation of the material, interaction with the foundation).

Notes: Conclusions 1. The inclination of impeller vanes should be increased to a final value of 80–130° near the outlet on a length corresponding to 15–50% of the total vane length. 2. To optimize the flow regimes it is expedient to install in the zone of the increased vane inclination 1–5 additional short vanes with a length amounting to 0.6–1.2 of the length of the swept-forward tips of the main vanes. 3. Impellers with an increased inclination of the outlet tips of the vanes and with additional short vanes in this zone increase the pump head by 30–95% for the same dimensions of the impeller and its rotative speed, increase the efficiency by 5–15% at high deliveries and by 1–3% at rated deliveries, and also increase the delivery by 5–80%.

Notes: Conclusions 1. The solution of problems of optimal selection of the number and composition of operating units for a given value of the total discharge of each pumping station will make it possible as a whole for the canal to reduce expenditures of electric energy for pumping the necessary volumes of water. 2. The mathematical approach to the solution of the given problem examined above is suitable for canals with open pools and with multiple-unit pumping stations having a considerable internal range of regulation.

Notes: Conclusion The proposed methods of calculating and analyzing the stability of rock slopes make it possible to obtain reliable results with consideration of the possible character of failure and degree of reliability of the initial information. These methods were widely used in practical calculations of the stability of rock masses and slopes when planning stabilization measures in the reservoirs of the Tolorossy and Zaramag dams (Armenian branch of Gidroproekt), Akhuryan dam (Armenian State Institute for the Design of Water-Management Structures), when investigating and designing the lock of the Dnepr-2 hydroelectric station (Ukrainian branch of Gidroproekt), and when investigating and designing the Middle Enisei hydrostation, Khudofera hydrodevelopment, Konstantinovka hydrostation and Tashlyk pumped-storage station, Southern Ukraine power complex, etc.

Notes: Conclusions 1. Improvement of the existing cyclic methods of constructing concrete dams in recent years made it possible to considerably increase the rate of placing concrete and to reduce the specific labor expenditures on placing 1 m3 of concrete in the dam. 2. There are ways to improve further each of the existing methods of delivering concrete to the block. The most promising are the craneless layer-by-layer, cableway, and crane trestleless (stepwise) methods. 3. Further progress in concreting technology as a whole should develop in the direction of improving all concreting operations, especially those within the blocks.

Notes: Conclusions 1. To predict the depth of a scour depression at the toe of a protected concave bank of a meander in gravel-pebble channels and to determine the rate of this scouring, a simplified calculation method was developed on the basis of analyzing the results of calculation by the complete method of the Institute of Fluid Mechanics, Academy of Science of the Ukrainian SSR. 2. The main conditions making it possible to use the simplified calculation method are: disregard of the balance of the bed load and the nonuniformity of the flow in the scour depression at the protected concave bank of meanders. To perform the calculation it is necessary to have the value of the average slope of the free surface of the water on the axis of the flow, which is assumed constant during deformation of the bottom of the meander. 3. In the calculation one determines the vertically averaged velocity of the nonuniform flow u2 and the friction velocity u*2 in the scour depression, which must be compared with the friction velocity u*p corresponding to the detachment of the erosion pavement of inhomogeneous soil composing the bottom of the meander. By assigning various values of deepening of the bottom Δzb in the scour depression, one finds the value of Δzb for which scouring of the bottom ceases (u*2=U*p). 4. To check whether the calculated deepening of the bottom can occur during the duration of the calcualted flood on the basis of the value of the bed-load discharge calculated by means of Einstein's graph, the rate of deepening of the bottom in the scour depression is determined with the use of the method given in [1] for this purpose. 5. The reliability of the recommended simplified calculation method is confirmed by the results of comparing the calculated and experimental values.

Notes: Conclusions 1. The main virtue of the multipurpose optimization method is the possibility of complete realization of the systems approach to justification of variants of development of systems. 2. The existing possibilities of a more thorough consideration of the output characteristics of systems by the method of minimum adjusted expenditures do not lessen the significance of the multipurpose optimization method. 3. Theoretical investigations conducted at Leningrad Polytechnic Institute showed that multipurpose optimization method makes it possible to show the advantages of hydropower installations more completely.

Notes: Conclusion Comparing the results of the prototype and model investigations, we can state that pressure fluctuations on the bottom of a gradually varied and markedly nonuniform flow (hydraulic jump) are reproduced sufficiently well on models of the structures, and the slight distortions of the energy-frequency spectrum caused by the nonmodelability of aeration and microturbulence of the flow can be disregarded. If it is necessary to conduct dynamic calculations of the structures, when a rigorous and spectrum-differentiated consideration of the pressure fluctuations is required, corrections obtained on the basis of the examined investigations (Fig. 3a, c) can be introduced. The intensity of the pressure fluctuations on the bottom of the flow under the free-falling flow under prototype conditions compared to the model data noticeably decreases due to aeration and fragmentation of the flow, which for all practical purposes are not reproduced in the model. When converting the data from the model to the prototype the correction factors given in Fig. 2 and Fig. 3b can be used as the first approximation in the investigated case. It is necessary to continue investigations of this problem.

Notes: Conclusions 1. The problem of calculating and predicting the ice and thermal regimes of modern large hydrostations being created, especially under northern climatic conditions, is important for solving many problems having national economic and nature conservation significance. The solution of the problem of reliable prediction of ice and thermal regimes in lower pools of large hydrostation is of particular interest and significance. 2. The presently existing methods of calculating the ice and thermal regime of pools of hydrostations are approximate and have been developed mainly with regard to the operating conditions of particular low- and medium-head hydrostations located, as a rule, in the temperate climate zone. They insufficiently take into account the specific characteristics of the physical phenomena governing the formation of the ice and thermal regime in lower pools. 3. As shown in the article, on the basis of an additional thorough study of physical phenomena with the use of data of actual observations it is possible to give a reliable picture of ice and thermal processes in lower pools of hydrostations, including those located under northern climatic conditions. With the use of the theory of heat transfer and refinement of the heat-balance equations analytic and graphic relations were obtained which permit determining the main characteristics of the ice and thermal regime in various stretches of the lower pool, longitudinal and vertical temperature distribution of the flow, and formation of frazil and the ice cover. In the future these relations can be refined with the use of mathematical modeling methods, comparison with actual data, and also with consideration of the possible effect of various additional factors in the lower pool (presence of the discharge of warm waters, unsteady flow regime during operation of the hydrostation, etc.).

Notes: Conclusions 1. A decrease of cement contents compared to analogous compositions of the Bratsk hydrostation, improvement of concrete quality, and increase of general technological discipline attest to definite progress in the technology of hydrotechnical concrete at the Ust-Ilim hydrostation. Further progress is associated with the selection of a rational technology on the basis of the experience of the Bratsk and Ust-Ilim hydrostations, modernization of individual components, and creation of a system of automatic compensation of the variability of the moisture content of aggregates at concrete plants, mechanization of concreting operations in the blocks, and increase of general efficiency. 2. Site tests of the concrete of the Ust-Ilim dam and the results of observations of seepage through the concrete of the upstream face showed that the solid concrete mass is practically impermeable and the relatively small seepage flow occurs along cracks and horizontal joints. One of the directions of the rational use of concrete can be a further reduction of the cement contents in concrete of the upstream column to an extent which does not cause damage when used as a material and will promote an increase of crack resistance of individual blocks and structures as a whole. 3. An analysis of the results of testing control samples and visual observations of the state of concrete surfaces showed that when assigning the concrete composition it is absolutely necessary to take into account the conditions of hardening of the concrete in the structure. In massive and underwater structures concretes with low cement contents harden most intensely and for the longest time. The strength reserves occurring in this case remain, as a rule, unused. In outer surface zones, conversely, early drying and other unfavorable factors can lead to a decrease of the potential possibilities of concrete. 4. The prescribed technical parameters of the concrete of the spillway surface and variable-level zone were completely provided as a result of introducing a number of measures: blending of special compositions, development of technology of placement, etc. The wider use of rubble in especially important concretes is characteristic for the Ust-Ilim hydrostation as a whole.

Notes: Conclusion On-site investigations and calculations of a transition structure make it possible to provide discharges under acceptable conditions if a vacuum is absent at the inlet section of their pressure pipes.

Notes: Conclusions 1. The bearing capacity of sand foundations of plates and their horizontal displacements are described by generalized graphs of the relation $$N_{\tau _{ul} } = f(N_\sigma )$$ and $$u_{ul} /B = f(N_{\tau _{ul} } )$$ , which is confirmed by the validity of the similarity parameters of the state of stress and strain of the foundation. The relations obtained indicate the possibility of conducting field experiments with small plates, for example, with a width of 0.7–1.0 m, which considerably reduces material and labor expenditures. 2. The aforementioned graphs are different depending on the state of the soil. The bearing capacity of the made-ground foundation is considerably less than that of an undisturbed foundation. In the first case the initial section of the graph $$N_{\tau _{ul} } = f(N_\sigma )$$ , within which the plate shifts along the plane, is limited by a critical modeling number $$N\sigma _{cr} \cong 1.0$$ . According to the results of field investigations it was $$N\sigma _{cr} \cong 4.0$$ . The revealed circumstances permit using the indicated graphs differentially as the maximum possible with consideration of the sensitivity of the soil.

Notes: Conclusions 1. Centrifugal pumps with an adjustable outlet diameter and width of the impeller passage and discharge pipe improve the operation of the netweork and make it possible to reduce energy expenditures at pumping stations by 10–20%. 2. By obtaining clean water directly from the sludge and directly in the pump (without pressure losses) it is possible to solve the problem of protecting pump elements from abrasion by a wall boundary layer without increasing energy expenditures on injecting clean water into the internal cavity of the pump. 3. By fractionation of sludge in pressure settling tanks (without pressure losses) it is possible to use inferior borrow pits near hydrotechnical construction sites for reducing transportation expenditures on delivering inert materials to the site.

Notes: Conclusions 1. Modeling of the cooling capacity of a water area without consideration of the weather and ice conditions does not give a true picture of the distribution of water temperatures. In connection with this, the data of modeling can be regarded only as a first approximation. 2. Dams with a gravel-sand foundation can operate reliably without constructing a stone bed. 3. Heating of the water at the intake in the winter, especially in the period of shuga formation, increases the reliability of operation of the power station. 4. When designing intakes it is necessary to take into account drift, gradient, and longshore currents. 5. Observations conducted at the Caspian intake show that dust particles falling on the surface of the canal are removed from the canal by the flow and the canal is not silted. 6. Cuts beyond the limits of levees are quickly filled with sediments and their construction is not advisable.

Notes: Conclusions 1. On the basis of analyzing the working conditions of elements of the lock gates on the Moscow Canal and on-site strain measurements the low-cycle character of loading and the possibility of failure in the maximally stressed zones as a consequence of the occurrence of repeated elastoplastic deformations in the structural material was confirmed. 2. It is necessary to calculate and determine experimentally the low-cycle life of elements of the load-bearing structures of lock gates and to work out recommendations on increasing their resistance to cyclic failure.

Notes: Conclusions 1. The wide range of computational, development, and experimental model investigations of the designs of high-pressure emergency-guard gates and main regulating gates, their movable parts and seals, hydraulic lifting gear of large capacity, gate chambers, and schemes of surplusing works performed in recent years showed the real possibility and economic expediency of manufacturing mechanical equipment for regulating large waste discharges at a head of 200 m. 2. Studies showed also the effectiveness of using the effect of swirling of the discharging flow in spillway systems. 3. Further perfection of the mechanical equipment of high-head spillways should improve the layouts, increase the precision and quality of manufacturing gates and drives, operating reliability of the seals, vibration resistance, and protection from cavitation.

Notes: Conclusions 1. At the current stage of development of hydrotechnical construction, when an ever greater scope of surveys is required for substantiating designs, a new approach to their planning is necessary — conversion to a survey optimization system. 2. One of the most effective ways of optimizing surveys is found at the junction between surveys and designing and consists in conducting calculations and design studies for analyzing the effect of geological factors on the preliminary designs, which makes it possible to reveal the most important factors and to arrange the types of surveys according to the degree of their significance for the given hydrostation and necessary detail of investigation. 3. It is necessary to introduce into design and survey practice a preliminary calculated design analysis at the stage of contract and, especially, detail designs, making it possible to establish the most optimal composition, scope, and method of surveys.

Notes: Conclusions 1. The solution of the three-dimensional problem of the state of stress and strain of a high earth-rock dam gives new information on the character of its behavior and permits a more realistic evaluation of its performance. 2. The behavior of an earth-rock dam in a canyon with a site coefficient equal to 2 is characterized by a substantial arching effect between the canyon walls and, since the level of normal stresses in the core is low, it is desirable to take technical steps to increase the crack resistance of the core. 3. The results of solving the three-dimensional problem confirm the intense decrease of horizontal displacements in the dam core, noted by the data of on-site observations. 4. A canyon shape curved in plan substantially increases the stability of a dam.

Notes: Conclusions 1. When creating mechanical equipment of hydraulic structures it is necessary to take into account not only the one-time expenditures on its creation and assembly but also its operational reliability, maintainability, annual costs for upkeep and repair of equipment, labor efficiency, and working conditions of the operating personnel. 2. One of the ways to increase the reliability of mechanical equipment is to develop standard criteria of its condition, such as longevity, technical life, no-failure operation, maintainability, keeping qualities, etc., which permit a confident determination of the actual reliability indices and prediction of its operational capability. 3. For developing the said criteria, determining numerical reliability indices of operating equipment, and determining the regularities of the change of these indices with time or as a function of the actual cumulative operating time of the equipment, it is necessary to generalize the available and collect missing data on the actual condition of mechanical equipment, its operation, and repair. 4. To increase the quality of evaluating the technical condition of mechanical equipment it is necessary to develop on the basis of technical diagnostic principles a method of evaluating the actual condition of equipment (with an indication of the composition of inspected elements for various types of equipment, criteria of their evident and indirect diagnosis, etc.) and instructions on predicting its further operational capability. 5. It is necessary to create portable diagnostic and monitoring and measuring equipment for conducting inspections in a volume sufficient for an objective evaluation of the condition and for predicting the actual reliability indices of mechanical equipment.

Notes: Conclusions Clays are the main component of grouts for creating grout curtains in alluvial soils. Clays of the montmorillonite group, which are exceptionally scarce materials, have found wide use in grouting works. The developed compositions of grouts have expanded the assortment of types of clays used for grouting works; they have made it possible to use in large amount certain local clays of the kaolinite group and also gypsified clays for preparing clay-chemical grouts. The experience of the wide introduction by Gidrospetsstroi of the developed composition of grouts in the construction of grout curtains showed their technical and economic effectiveness.

Notes: Conclusions 1. Tests on the surge towers of the Mingechaur hydrostation showed that quite considerable corrosion rates can occur on these structures. 2. To prevent corrosion of these structures it is recommended to use cathodic protection with groups of anodes echeloned over the height.

Notes: Conclusions 1. For hydrostations with a small storage capacity of the reservoir located under harsh climatic conditions it is often necessary to provide for the possibility of passing ice through spillway outlets of the dam and to take into account dynamic ice loads when designing mechanical equipment 2. For repairing the spillway part of the dam it is expedient to use caisson gates, and for newly designed hydrostations to provide for fixed parts of the guard gate. 3. Low-cycle fatigue and stress concentration can be one of the possible causes of destruction of the gates. 4. The existing methods of determining the load on the wheel supports of the service gates give a sufficient margin ensuring their long-term operation. The method of determining the load on the side guides of the gates with two points of suspension requires correction. 5. It is recommended to provide a gantry crane for servicing the mechanical equipment of overflow dams having two or more outlets.

Notes: Conclusions 1. The absence in designs of mechanical equipment of decisions about the use of permanent or universal temporary gate-operating mechanisms in the construction period hampers the construction of structures, especially in the period of preparation for start-up. 2. It is necessary to introduce into the technological design standards of hydroelectric stations VNTP-12-77 the requirement of the possibility of operating the service gates at any degree of readiness of the structure. 3. The existing designs permit creating a knockdown device for controlling the gates of hydrostations during construction.

Notes: Conclusions 1. The decrease in the consumption of metal due to using high-strength steel IZ-6 in the manufacture of the pipes saved 300 tons of steel. 2. The designed tees and wyes provided a minimum number of assembly units and thereby increased the technological efficiency in the manufacture and assembly of the pipe. 3. The technology of assembling pipes in a 212-m-deep vertical shaft and in horizontal tunnels with a small annular was developed for the first time. 4. Self-propelled mechanisms, which made it possible not only to deliver links to the assembly site over a distance of 1.5–2 km, but also to adjust them for assembly, were used for the first time. 5. The pipe was assembled in the 212-m vertical shafts by means of a 40/10-ton gantry crane, and emergency and construction hoists, which provided complete safety of the works. Newly developed suspended platforms were also used for the vertical shaft instead of labor-intensive, material-consuming scaffolding over the entire height of the shaft. 6. The developed technology of assembly works and adopted mechanization of the assembly of the pipes in tunnels made it possible to reduce the cost and save about 1.2 million rubles due to a reduction of rock excavation and concreting works (compared to the 1-m annular needed according to the old technology), in which case 35,560 m3 of excavation and just as much concrete were saved and also provided safe conduction of the works; labor productivity increases by 1.5 times, which reduces labor expenditures.

Notes: Conclusion It is recommended to use the given relationships when designing dikes of reservoirs operated under conditions similar to the conditions of the Kiev PSS reservoir [3–5]. To refine a number of the foregoing assumptions and proposed relationships, it is expedient to continue hydrophysical investigations of the dynamics of formation of the structure and mechanical strength of the layered ice prism on the slopes of the dike of the Kiev PSS reservoir. The materials presented and also the data of on-site observations can serve as grounds for developing as a first approximation a method of designing revetments of dike slopes of PSS reservoirs for the effect of ice.

Notes: Conclusions 1. The operating conditions of a dam on undermined territories substantially differ from those under ordinary conditions (without undermining). This necessitates a special approach to the design and operation of such dams, since the use of the experience of conventional hydraulic engineering is not possible. 2. The occurrence of cracks in the foundation in the case of undermining unloads the soil mass adjacent to them. Further deformation of the mass occurs due to an increase in the size of the primary cracks (practically without the occurrence of new ones), which is the main characteristic of deformation of earth dams on undermined territories. 3. The use of nonsoil materials for watertight elements (WTE) of dams (asphaltic concrete, polymer films) cannot completely eliminate and cannot change the regular mechanism of cracking in their body, consequently disruption of the continuity of such elements is completely possible. Therefore the use of the indicated nonsoil materials as WTE, in principle, requires further investigation. 4. All the aforesaid brings to the forefront as the most promising direction of investigations the development of fundamentally new designs and technological measures to ensure reliability of earth dams on undermined territories.

Notes: Conclusions 1. A considerable difference was established between the actual data and the current standard recommendations on calculating the Chezy coefficient of earth canals, leading to negative economic consequences and being, in turn, the result of insufficient correspondence of the formulas used for the Chezy coefficient to the character of hydraulic friction. 2. On the basis of the new relation (3) and mass homogeneous actual data, Eqs. (20) and (21) were developed, which substantially refine the calculation of the Chezy coefficient of earth canals and lead to more economical decisions. 3. Equations (20) and (21), with values of the parameters for canals in cohesive soils under normal conditions, were substantiated in wide limits and are recommended also for calculating the appropriate stretches of the main Ob-Amu Darya diversion canal. 4. The results of the present investigation, being a further confirmation of the rationality of Eq. (3), show also that the classification of earth canals according to their size (MSÉS standards) or discharges (Gosstroi standards) used in engineering hydraulics is a forced artificial and quite inadequate measure called on to mollify the noncorrespondence of the formulas used for the Chezy coefficient to the character of the phenomenon. The relations obtained in the work permit dispensing with such a classification. 5. The result of the present investigation are recommended as the basis for revising the standard recommendations on calculating the Chezy coefficient of earth canals.

Notes: Conclusions 1. It is necessary to develop a special method of evaluating the cost effectiveness of an ACS TP HES with consideration of the suggestions expressed in this article. An evaluation without consideration of additional substitution of the capacity substantially underestimates the effectiveness of an ACS TP HES. 2. When designing an ACS at HES being newly constructed, it is necessary to design a variant of combining the ACS with the local control equipment and to eliminate the superstructural variant. Only at operating HES with special justification can the superstructural ideology be permitted in the creation of the ACS.

Notes: Conclusions 1. The work of the film membrane can be considered sufficiently effective. 2. Increased seepage through the grout curtain in the rock walls (especially on the right one) is leading to discharge of seepage waters on the downstream shoulder of the dam. In this connection it is recommended to install drainage in the downstream slope of the dam with discharge of the water below the depth of freezing. Further on-site observations of the discharge of seepage waters and presence of piping particles in them are necessary for determining the need for reinforcing the grout curtain in the canyon walls.

Notes: Conclusions 1. Hydrochemical methods of investigating the seepage flow under conditions of the Irkutsk hydrostation should be used in combination with traditional methods of observing the condition of the structures. 2. As indicators of the seepage flows and subsurface waters it is possible to use, along with mineralization of the water, the content in water of C1− ions and the sum of the derivatives of carbonic acid ∑C02, which in certain cases give a more accurate idea about the seepage flow in the foundation when determining the effect of water on concrete of the structures and grout curtain. 3. Having distributed the content of the indicator (total ions, Cl−, ∑CO2) in the piezometers along the equipotential lines of the seepage flow net, we can obtain a clear picture of the distribution of seepage flows and subsurface waters in the foundation and body of the structures. It is necessary to note that the seepage flow net obtained by calculation or on the EHDA instrument does not always correspond to the actual picture of seepage, which somewhat reduces the accuracy of the proposed method. 4. The preliminary conclusions about the mechanism of interaction of the seepage flow with concrete of structures require further refinement by setting up broader hydrochemical investigations of seepage, including seepage through cracks in the concrete.

Notes: Conclusions 1. Investigations of unstrengthened and strengthened materials with the use of the large testing device confirmed the conclusion made earlier concerning the effectiveness of filling in rock fill for increasing the strength of earth masses. 2. Experiments showed the possibility of using noninfilled and infilled rounded stone, which broadens the area of use of boulders and cobble in construction, where presently such material is graded out. 3. The low compressibility [2] and high shear strength of infilled rock fill permits hoping for the wider introduction into hydrotechnical practice of dams with facings if strenthening of the shoulders by infilling is mastered. 4. For more substantiated conclusions with respect to this matter it is necessary to conduct a wide range of laboratory, field, and theoretical investigations. In so doing it is necessary to bear in mind that filling in rock fill complicates the technological process and therefore should be technically and economically justified and coordinated with the local construction conditions.

Notes: Conclusions 1. Flatland rivers on long stretches have a sufficient reserve for passage within their banks of increased dry-weather discharges without adverse consequences. 2. The passage of increased dry-weather discharges in individual stretches of flatland rivers has a favorable effect on the development of flora and fauna of the floodplain. 3. In the case of interbasin water transfer a decrease of bottom sediments will occur due to the discharge of clarified water, which in the future will lead to a further increase of the channel capacity. 4. The use of channels of flatland rivers for interbasin transfer without performing dredging works produces a substantial economic effect. 5. The theoretical investigations and development works performed and also the planned full-scale investigations can be used when working out interbasin water transfer projects with the use of the channels of existing rivers.

Notes: Conclusions 1. Operators should not violate the rules of operating gates established in designs on the basis of hydraulic investigations. 2. An increase of the resistance of uplift and withdrawal of the apron slabs of the bottom of a dissipator should be achieved primarily by anchoring them to the foundation, which also saves construction materials. 3. Protection of the surface of slabs and blocks of a dissipator from abrasion is achieved by placing on the slab surface a wear-resistant layer of high-grade, heavily reinforced, well-compacted and cured concrete prepared with strong crushed rock.

Notes: Conclusions 1. Initial welding stresses occurring during welding of reinforcement splices in the joints of precast reinforced-concrete flexural members can be used for increasing the rigidity and crack resistance of their interblock joints. 2. The necessary level of the initial tensile welding stresses can be determined from the condition of equality of the linking joint and monolithic cross section of the precast blocks. 3. The concrete sealing the welded splices of the reinforcement projections in the joints of precast reinforced-concrete members is less prone to cracking as a consequence of the jig effect exerted on it by the compressed concrete of the precast block.

Notes: Conclusions 1. Investigations, design, and operation showed the technical and economic expediency of using epoxy-bitumen coatings as waterproofing of hydraulic structures related to the passage, storage, and treatment of potable water. 2. The most effective area of use of epoxy-bitumen coatings is for waterproofing thin-walled non-crack-resistant components and structures.

Notes: Conclusions An experimental check of various low specific-speed pumps showed that on changing the geometry of the vaning of the impeller, in conformity with the recommendations [1], the main feature of which is an increase of the outlet angles of the vanes to values 90°≤β2≤130° and installation of short intermediate vanes in the passages between the main vanes, the head increases considerably without a decrease of pump efficiency. For centrifugal pumps with a volute and diffuser whose impellers have a different number of main vanes, the most rational is the installation of three intermediate vanes in each vane passage with a change in the direction of the flow by the main vane toward an increase of the outlet angle on diameter D2=0.5–0.65D3 for fecal pumps and pumps with short vanes. The use of the new impeller design is especially effective for high rotative-speed pumps. For multistage submersible pumps with a guide-vane apparatus at the inlet and axial outlet, the optimal variant is the installation of one intermediate vane with a start of the change in the flow direction D3=0.63D2. In conclusion, it is necessary to note that all tests were conducted without modifying the casing and branch pipes, which leaves room for a further increase of the head developed by pumps with the new type of impeller.

Notes: Conclusions The investigations permit recommending the ultrasonic method of determining the frost resistance of concrete on specimens at construction laboratories and other organizations, when correcting concrete designs, for prompt checking of its quality, and when evaluating the frost resistance of concrete in structures under construction and in operation on the basis of cores. The ultrasonic method of determining the frost resistance of concrete is based on a comparative testing method with the use of calibrated relations between compressive strength, ice content, ultrasound velocity, and frost resistance of concrete of known designs. A check of the accuracy and reliability of determining the frost resistance of concrete by means of the calibrated relations “parameter i/Rcm-frost resistance” showed that a relatively high accuracy of determining the frost resistance of concrete, equal to ±15%, can be obtained in 95–98% of the cases. This permits raising the question about adding the necessary recommendations to the appropriate standards.

Notes: Conclusions 1. When designing pumping stations, it is necessary to specify in the design pressure leads for head flowmeters on elbows of pressure pipes and segment orifice plates in the case when there are no elbows. 2. It is necessary beforehand to provide for and assemble devices facilitating the measurement of discharges when testing pumps and calibrating flowmeters.

Notes: Conclusions 1. At present rock slopes are usually designed on the basis of the most unfavorable (of those possible) arrangement of potential shear joints in the investigated mass and without consideration of the probability of the presence of joints of such orientation in it. 2. A new method is proposed here for calculating the stability of rock slopes based on the use of a statistical probabilistic method of processing the measurements of orientations of potential shear joints and taking as the criterion of stability of slopes their reliability value. 3. The practical use of the method when designing the rock slopes of foundation pits of the Southern Ukraine power complex showed the advantages and prospects of the probabilistic approach to estimation of the stability of masses. In particular, use of the method made it possible to design some steeper slopes, which as a whole for the complex will permit avoiding additional excavation of tens of thousands (potentially as much as 160,000) of cubic meters of rock. 4. The results of calculating slope stability for various values of the hydrostatic pressure indicate the need for special investigations (e.g., on an electrohydrodynamic analogue) to determine the shape of the line of seepage in masses and the expediency of refining this line during excavation works.

Notes: Conclusions 1. It is most rational to compact gravel-pebble and sand-gravel soils in dams to a relative density JD=0.8 (coefficient of compressibility RD=0.97). It is recommended to take this into account when revising construction specifications and regulations SNiP II-53-73 “Earth Dams”. 2. Deviation from the indicated control relative density leads upon its increase to a marked increase of energy expenditures on compacting the soil and upon its decrease to the incomplete use of the strength and deformation properties of the soil. Such devitations require special substantiation in designs. 3. It is necessary to take into account that the investigated soils, as a rule, contain silt and clay particles, and therefore have an optimum moisture content whose value can be determined experimentally. 4. In the absence of experimental values of the extreme density, the dry density of of gravel-pebble and sand-pebble and sand-gravel soils can be assigned on the basis of their actual values in nature.

Notes: Conclusions 1. The new design of the rectangular stilling basin with the addition of an overhanging deflector of the calculated dimensions along the upper edge of the basin intensifies dissipation of the kinetic energy of the nappe by creating a circulating, eddy flow in the basin. 2. The dimensions of the basin of the new design are smaller compared to a basin without a deflector. 3. An experimental check on a model of the new basin design made it possible to introduce it in the construction of hydrostations. Long-term experience in operating the basin showed the reliability of its action and proved the expediency of using it under other analogous conditions.

Notes: Conclusions 1. Equation (2) can be recommended for determining the coefficient of wave suppression by a structure with an incomplete vertical profile. 2. To determine the wave loads from breaking waves on structures with an incomplete vertical profile one can use the appropriate recommendations of SNiP II-57-75 with consideration of the aforementioned corrections with respect to calculating the horizontal and uplifting forces of the wave pressure.

Notes: Conclusions 1. According to the results of a technical-economic analysis the technology described above can used widely at medium-head small-unit hydrostations with Francis turbines. 2. An experimental check of this technology is needed for a more complete evaluation of its positive and negative aspects.

Notes: Conclusions 1. A method of harmonic search for the optimal order of arrangement of poles is proposed. The method is a mathematical apparatus for solving the problem of the best self-balancing of the rotor pole system of a generator and is free from restrictions on the relationship of the masses of the poles or their number. 2. The method is realized in a high-speed program for a computer. As a result of numerical calculations, variants of the arrangement for which the pole system is practically completely self-balanced are obtained.

Notes: Conclusions The use of jointless assembly of the stator considerably complicates installation of the unit. It is far faster and simpler to assemble the stator from individual ready-made sectors. It is impossible to create on the assembly floor conditions for providing the required quality of assembling a jointless stator. The entire assembly process was performed in temporary structures — tents — in which it is difficult, and at times impossible in the case of combined assembly of the stator and turbine, to maintain a constant temperature and to keep out dust and precipitation. So far the advantages of a jointless stator have not been determined since at present the assembled units have 50–60% of the rated load. It is impossible to make any practical conclusions about an increase of core life. The test engineers of Elektrosila repeatedly measured vibrations and other characteristics of the stator. The results are positive, they are being generalized. It will be possible to make final conclusions when the units are operating at full capacity, but theoretically the jointless stator is indisputably progressive.

Notes: Conclusions 1. Of the two examined schemes of laying out vertical units preference, in our opinion, should be given to scheme I (two-bearing with an umbrella-type generator) in view of a number of advantages of this scheme over scheme II (three-bearing with an overhead generator). 2. Other unit layout schemes also deserve attention, but they should be analyzed thoroughly, including from the viewpoint of the technological efficiency of the unit in assembly and maintenance. 3. A three-bearing scheme with an umbrella-type generator was used for the first time in laying out the unit of the Kolyma hydrostation. The experience of assembling the prototype of this unit revealed a number of shortcomings of this scheme with respect to its technological efficiency in assembly and maintenance. From this viewpoint, after conducting full-scale tests of the prototype it is advisable to use one of the examined schemes (scheme I or scheme II) when arranging units with diagonal-flow turbines.

Notes: Conclusions 1. The six units of the Sayano-Shushenskoe hydrostation were installed in the shortest possible time with combined construction and assembly works. Despite this, four of the six assembled units were accepted by the state commission for operation with an evaluation of “excellent.” 2. The equipment was assembled at a modern technical level. Progressive technology based on mechanization of the majority of labor-intensive works is being used by the Bratsk Installation Administration of Spetsgidroenergomontazh in performing assembly works on the hydropower equipment. 3. A large economic effect was obtained thanks to enlargement of the components and blocks of the units in advance, which here amounted to about 85% of the total volume. 4. A substantial role in increasing the efficiency of assembly works was played by the agreement of cooperation between the assemblers and operators, which stipulated: component-by-component delivery and acceptance of all components of the assembled equipment; performance of all reconstruction works during assembly of the units, the need for which is revealed by operating experience; adjusting, regulating, and making ready the operation of the unit under a load with a high degree of efficiency. 5. One of the factors that had an effect of shortening the time of assembly works was the introduction of a crew contract on the main construction and assembly works, which made it possible to reduce the cost of assembly works and increase the material incentive of the workers. In the contract crews the annual output per worker amounted to 16,248 rubles vs 15,469 rubles for the entire administration.