Vol 52, No 6 (2019)

The natural characteristics of the formation of proluvial deposits necessitates regulating their particle size distribution and moisture content before placement in the dam body. Soil material can be created from proluvial deposits for various zones of the dam body, including rubble-clay soil for impervious components, which with proper compaction, is characterized by high seepage, piping, and mechanical strength as well as small compressibility. It is advisable to carry out quality control of compaction of such soil on the basis of fines.

A modern approach to geotechnical monitoring of works on strengthening the rock slopes of hydraulic structures with solving the problem of optimizing the selection of the type and parameters of the supports is proposed.

The ARTEMIS model is used to numerically analyze the wave conditions near the Sabetta-Utrenniy port of different layouts. Monochromatic and spectral waves were considered. The results show that a navigation channel can not only cause strong focusing of wave energy, but also give rise to zones of reduced waves. It is important to recognize these effects and use them to optimize the project.

The results of field studies of rigidly anchored retaining walls are described. Design solutions for mooring-and-guiding structures of the Bagaevsky lock are justified. Recommendations for the design of rigidly anchored structures are formulated.

Using the Midas Civil 2011 software system, numerical studies were conducted of the temperature regime and thermal stress state of a concrete massif during its construction, for the cases without the use of, and with the use of, pipe cooling. The usage of pipe cooling made it possible to exclude the occurrence of critical values of temperature gradients and thereby minimize the risk of occurrence of thermal fractures.

Creation of a high-tech zone from stone concrete to serve as a transitional solid between the reinforced concrete face and the stone of the blockweight is proposed as a way of improving the stress state of the reinforced concrete face, increasing its reliability, and creating conditions by means of which repair activities may be performed without drawdown of the reservoir. Stone-concrete is a material with low content of cement (65 –70 kg/m³) produced by pouring a cement-sand solution of backfilling composed of crushed rock or gravelly-pebbly soil in a layer up to 0.5 m high. The optimal composition of the poured mixture for stone-concrete is selected from the need to achieve complete penetration through the pores of the backfilling, fill the pores, and create a conditionally “solid-cast” structure. The study presents data for the selection of the composition of the poured mixture for stone-concrete and provides tables and graphs of relationships by means of which the properties of the resulting material may be predicted as a function of its composition.

The reinforced concrete structures of hydroelectric power plants and nuclear power plants differ from civil structures by their massive nature, including high cross-sections, low reinforcement percentage, and the presence of block seams. A decrease in the safety of these structures results when these features are not taken into account. Methods of calculation that take these features into account are proposed.

The chief issues in the operation of combined-cycle power plant (CCPP) heat recovery steam generators at the stage of maturation of this technology in the power industry of Russia are outlined. The design evolution is shown for heat recovery steam generators (HRSG), reflecting the problems of ensuring rapid start-ups of CCPPs and limiting the failure rate of thick-walled elements of the HRSG steam-water path; and an approach is proposed for designing programs for maintenance of heat exchange steam generators.

The great practical significance of a computational determination of the frequency characteristics of the front parts of turbogenerator stators for assuring reliable and safe operation is noted. Critical questions related to computational determination of the eigenfrequencies are considered as are different computational techniques. A combined computational and experimental method of determining the frequency characteristics based on the method of finite elements in a three-dimensional formulation is proposed. The basic steps of the method are considered and special attention is devoted to the stage of developing boundary conditions in light of the data of experimental investigations. Results of a comparison of the computational and experimental spectrum of the eigenfrequencies of the output buses are presented.

The repowering project of the Nizhnekamsk CHPP involves upgrading the main and accessory boiler equipment to allow flame combustion of pulverized petroleum coke (petcoke) produced by a TANEKO delayed coking unit. The scope of work includes equipping the gas-and-oil fired boiler with a burner arrangement for petcoke combustion and providing central coal pulverization and pneumatic ash handling. To meet the atmospheric emission requirements, it is necessary to equip the boilers with a selective catalytic reduction installation, high-efficiency electrostatic precipitators, and a desulfurization plant.

For full use of information in multiparameter relay protection it is advisable to use statistical detection theory and a Bayesian criterion of minimal average decision risk. A method for combining the signals from a set of separate relay protection starters is proposed in order to improve its sensitivity. It is shown that combining the measurements of the univariate relay protection measurement devices yields the same result as combining the binary signals of starters using these measurement devices.

Scrubber operations were studied using the Flow Vision software system, which made it possible to obtain a picture of the distribution of velocity, temperature, and pressure fields of the flue gas inside the scrubber, and estimate the operation of the gas distributors and intake equipment based on the standard deviation of the modulus of the axial speed. Based on the analysis that was conducted, design changes were adopted that are based on the design of flue gas cooling scrubber by refinement of the ammonia-sulfate desulfurization process.

A classification of devices incorporated into flexible AC transmission systems (FACTS) in electric networks is presented. The characteristics of flexible AC transmission systems are considered, in particular: devices for compensation (regulation) of reactive power and voltage connected to networks in parallel; devices for compensation (regulation) of the network parameters (network resistance) connected to networks in series; devices that combine the functions of the two groups, i.e., direct-transverse connected devices; devices for storage of electric energy; and converters of the type of current (AC into DC and DC AC); and lines of a new generation of electric transmission lines with increased carrying capacity in combination with FACTS devices.