"Вестник МГСУ"

In the article the author describes the importance of the technological regulations development in the process of constructing various transport constructions: tunnels, subways, bridges and other important objects. In the article the peculiarities of the tech- nological regulations development are fully taken into account; the dependence of the depth of their development and the quality of the concrete constructions, as well as the speed of the objects of transport infrastructure construction, including the examples of building the road tunnels in Moscow. The course of their development is shown with account for the main provisions, which should be included in technological regulations in order to ensure the most complete coverage of the issues arising in engineering, laboratory and Supervisory structure in the process of performing the works. The author proposes new effective materials and technologies of works. In particular, sufficient attention is paid to self-compacting concrete — a new type of concrete, which is able to flow and compact under its own weight, completely filling the formwork even in case of dense reinforcement, while maintaining the homogeneity and having no seals. The application experience of concrete self-sealing in the construction of the metro showed that labor costs for the concrete mixture sealing were 5-6 times reduced, and the speed of laying the concrete increased 2-3 times. When laying self-compacting concrete high-quality surfaces are formed, which do not require additional costs to bring them to the design parameters. In addition, the work shows the parameters of the technological processes and sets various types of works sequence: the article describes the features of formwork, placement and curing of the concrete in terms of year-round construction, shows the importance of thermo physical calculations of concrete hardening and the efficiency of using self-sealing concrete. Sufficient attention is also paid to the methods of quality assurance and to the methods of preventing cracking of various structural elements of a construction, as well as to the safety requirements and ensuring proper protection of the environment.

In the process of developing wet cohesive soils (especially at cold temperatures) sticking and freezing of soil on the operating elements essentially reduces the machines performance. The performance decrease happens due to the reduction in the useful capacity of the scoops and due to incomplete unloading, the growth of frontal resistance at cutting (digging) as a result of wet ground sticking to a working part and also the resistance of the input into the scoop and increase of machine downtime due to the need to clean the operating elements. One of the most effective ways to reduce the adhesion of soils at the temperatures below zero is effecting with thermal and vibrothermal intensifiers.The article presents the analysis of shovels performance and soil frictional resistance inside the scoop. The proportionality coefficient or reduced friction coefficient takes into account the shift peculiarities when determining the soil friction force on metal surface, and its value includes deformation and adhesive components and depends on the same parameters as the shear resistance, namely, the time and the contact pressure, humidity and dispersity of soil, temperature in the shear plane, the surface state of the metal.Experimentally with the use of a special bench shift values the proportionality factor was determined depending on the temperature in the shear plane without affecting intensifiers, which reduce adhesion, and also at thermoacoustic and thermal impact. The results will allow calculating the frictional force on the metal surface of the operating element, taking into account adhesion and intensifiers effect. The obtained data will help to select the type of intensifier.

The article provides the information on a promising technology for trenchless repair named Swagelining, which supposes pulling into the old pipeline the new polymer with its preliminary thermo-mechanical compression and further straightening. The coauthors present the results of the calculations determining the thickness of the polyethylene pipes after compression and straightening in the old pipeline depending on the initial diameter in case of different ratio of the diameter to the wall thickness (SDR) and the dynamics of the changes in hydraulic performance after repair work on the pipeline using the method Swagelining. The concept of the energy saving potential is formed in addition to a no-dig repair for pressure piping systems, water supply, and its magnitude. On the basis of the research results, the authors formulate the principles of the energy efficiency potential after the implementation of the trenchless technology of drawing the old pipeline with new polymer pipes with their preliminary thermo-mechanical compression and subsequent area enlargement. The technology Swagelining is described and the authors develop a mathematical model that illustrates the behavior of the pipeline in the process of shrink operations. Such parameters are analyzed as changing the diameter of the pipeline at thermo-mechanical compression, the hydraulic parameters of the new (polymer) and old (steel) pipelines, energy savings on one-meter length of the pipeline. The calculated values of the electric power economy on the whole length of the pipeline repair section with a corresponding flow of transported waters.The characteristics and capabilities of the technology of trenchless renovation Swagelining allows achieving simultaneously the effect of resource saving (eliminationof the defects and, as a consequence, of water leakage) and energy saving (reduction in the water transportation cost).A numerical example of the old steel pipeline renovation shows the calculated data, which proves the efficiency of the considered technology. The calculation results can be used as base material for designers when selecting the final decision of the alternative at reconstruction of dilapidated pipelines by Swagelining using a wide range of polymer pipes with the corresponding value of the SDR.

The article describes various methods for solving problems of nonstationary heat transfer. Nonstationary heat transfer is characterized by the fact that the temperature changes not only from point to point, but also in time. The process of cooling metal blanks must be considered a transient thermal conductivity. When solving the problem of cooling metal blanks we need to find the temperature change in the section. The authors show the complexity of the tasks of nonstationary heat transfer. If we consider the process of cooling metal billets as a complex process, in which the addition of nonstationary heat transfer is presented as a process of heat transfer by radiation, great probability of errors in calculations occurs. There is the feasibility of the use of experimental researches of cooling processes for metal blanks after continuous casting, in order to determine the error in the calculated values.

Based on the comprehensive research and industrial development there is a new method developed for accelerating the hardening of foamed products using thermal heating of products by soft modes, which allows to receive high quality material and organize energy-efficient and environmentally friendly production of foam concrete products.

The method and low-energy intensive technology of manufacturing products of foamed concrete are developed providing bringing-in a solar energy in technological conversion for reducing the energy consumption for heat treating, allowing to obtain high quality products at low cost with a diurnal cycle of production. Thereby, the use of a minimal amount of additional electrical energy is stipulated for providing a consistence of temperature fields in the cross section of helio heated products in landfills in combination with solar energy. Until now, many scientists have investigated the issues of using the renewable energy resources in the construction industry including solar ones, for replacement of conventional fuels applied in the thermal treatment of concrete products and structures. However, pursuant to the analysis of the scientific literature, all known research studies and developments in this area are devoted to heliothermal treatment of conventional concrete, and at the same time the traditional methods for acceleration of hardening requiring significant energy consumption are still in use in production of such an effective building material as foam concrete. There are various methods of heliothermal treatment including combined ones, but they are not applicable in their production due to the specific characteristics (unlike conventional concrete) of manufacturing technology, the used components, the particular rheological properties, as well as a porous structure of foam concrete. Both the examining the use of solar energy in acceleration of foam concrete hardening according to the literature data and the pre-studies have revealed a problem under unilateral heliothermal treatment of foam concrete. It is found out that the temperature field of across thickness of the massif, especially during the first 7-8 hours, is irregular, that significantly affects the process of heating moisture transfer occurring within the massif. According to the previously obtained data, there is the highest uniformity of moisture distribution efficiency and thereby a maximum strength uniformity of products under bilateral supply of heat to the hardening concrete. On this basis, it is advisable to use both solar and additional electric energy having impact of periodic and short duration on the hardening concrete for the intensification of the foam products hardening in landfills in order to ensure a uniform heating of products and reducing temperature gradients. Calculations showed that the duration of landfill operation on production of foam concrete products for the areas of Central Asia located in 46° N is 8 months per year, i.e. from March to October. In order to achieve the greatest effect in the process of applying the developed method for complex heliothermal treatment of foam concrete products, there is a need in a steady warm and clear weather when the ambient temperature at noon reaches the values higher than +20 °C. It is found out that high strength characteristics can be achieved under optimum combination of exotherm of cement in foam concrete with soft modes of warming-up and cooling down of products.

Continuous technological advancements introduced into geodetic meters produce a significant influence on methods of and instruments for identification of settlements and horizontal displacements of such unique engineering structures as elementary particle accelerators, high-precision directional control equipment, radio telescopes, TV towers, etc. Against the background of intensive development, the microwave technology largely and effectively employs high-precision optical range finders capable of taking linear measurements with an error of 0.1—0.5 mm. Researchers of Yerevan State University of Architecture and Construction (YSUAC) continue the implementation of their geodetic meter project that contemplates mprovement and modernization of high-precision optical range finder DVSD-1200.The author presents distinctive properties of new advancements introduced into optical range finder DVSD-1200. The research into the characteristics of the optical range finder and experiments with different types of reflectors have caused the author to make a conclusion that the receiving optics is to be incorporated into the item that serves as the subject of research.

The article represents a summary of findings of various research projects aimed at the optimization of specific items of small size machines developed and pilot tested at different stages of construction operations.For 15 years, Department of Mechanization of Construction Processes, Kharkiv National University of Civil Engineering and Architecture has been engaged in design, pilot testing and monitoring of practical application of small size construction machinery. All machines and items of equipment have adsorbed numerous research findings, and no similar products are available in Ukraine and worldwide.The authors analyze different items of construction machines that have already been tested in the course of construction operations. They include a twin-piston coun- terflow mortar-and-concrete pump, two-piston direct-flow mortar-and-concrete pumps equipped with ball valves, spring valves and disk valves, advanced cascade concrete mixing machines. Each of the above machines can operate in pursuance of a pre-set pattern of shotcrete operations.All machines are universal, as twin-piston concrete pumps may pump concrete mixes having different workability rates; they can also be used to transport building mixes in horizontal and vertical directions; they are applied for shotcrete operations. They are efficiently used in the preparation of different mixes.All machines and items of equipment are protected by Ukraine-wide patents. They are recommended for wide-scale use due to sophisticated structural solutions invested into their design.

The article represents an overview and analysis of trenchless technologies used to provide for the leak resistance and strength of dilapidated sections of pipelines made of ceramics, cast iron, asbestos cement and other materials. Sectional pipeline repair technologies, considered by the authors, include those for the repair of loose joints of straight sections of pipelines and loose joints in the points of connection to secondary pipelines. Technologies analyzed by the authors also include those applied for the restoration of pipe shell cracks. Organic resins and bandages are to be used as repair materials.Besides, the authors provide detailed descriptions of the composition and properties of pumping resins injected into pipe cracks to restore the structural strength of pipelines and to assure their further reliable operation.Moreover, the authors assess the basic strengths of the bandage technology, including its low cost, low time consumption, and suitability to various types of pipeline damages (depressurization of joints, cracks, leaks, etc.). Besides, this method does not require any excavations, trenches, hoists or other machines.In particular, sections of underground pipelines, having diameters of 150 – 180 mm, may be repaired by specialized repair robots. Robots may be equipped with special-purpose devices, including cutter heads, bandage application heads, and color motion cameras. Besides, sectional repair of pipelines, having the diameter of up to 600 mm, may be performed using robots produced by Hachler Umwelttechnik, which are particularly efficient if the repair work is needed to be performed in the points of pipeline branching.The choice of specific pipeline repair methods and substantiation of their application are mainly driven by (1) the post-cleaning condition of a pipeline, (2) the findings of the telediagnostics, (3) options for arrangement and use of specialized machinery on location, and (4) feasibility of the pipeline operation in the course of repair works and procedures.

The authors consider particular methods, technologies and organizational aspects that may be implemented in the construction and renovation of pipelines using polythene materials instead of metals due to their economic and practical efficiency. It is noteworthy that the corrosion problem of steel pipelines is the phenomenon of metal destruction that reduces the throughput of pipelines and facilitates obstructions, juncture cleavages and water leaks as a result of reduction of service lives of pipelines. The authors analyzed the efficiency of polythene pipes from the viewpoint of hydraulic processes and the economic expediency; the authors identified that the polythene pipe’s throughput is 3 times as much as the one of steel pipes. Also, the authors determined the economic efficiency of polythene pipes: USD 0.5 million per 1 kilometer of pipeline.The authors take account of the technology-related aspect, as the water pipeline construction and reconstruction processes are limited by dense urban environments or due to the absence of overhaul factories in the close proximity to pipelines. Therefore, the results of the analysis evidence the efficiency of application of polythene in construction and reconstruction of pipeline engineering systems. It is highly resistant to abrasion and corrosion; it boosts the water flow velocity due to the low rough-ness of the internal surface; its service life is long enough, and its transportation is problem-free.

The essence of the new development, proposed by the co-authors, consists in the following engineering solution: a concrete spreader, designated for the molding of products to be made of concrete mixtures and composed of a self-moving gantry, is equipped with a hoisting smoothing mechanism and a cart having a travel mechanism that has a roll-over hopper and a dispenser with a shutter, that is kinematically connected to the power engine. The shutter has an elastoplastic lining. The hoisting smoothing mechanism represents a rack having rigidly connected top and bottom plates. The longitudinal groove of the smoothing plate has teeth with a conical body. The teeth are attached to the springs hinged to the bottom surface of the top plate rigidly connected to the rod of the hydrocylinder and a frame installed on the guide of the gantry. The proposed construction of the vibration-induced smoothing rack of a concrete spreader improves the quality of the smoothed surface of concrete mixtures thanks to the higher intensification and compaction of the concrete mixture surface because of deeper penetration of vibrations into inner concrete layers and higher pressure produced on the concrete mixture.

Modern turbochargers are important components to reduce the gasoline consumption on actual and future engines. The reduction of the cubic capacity (downsizing) of an engine with a simultaneous increasing power, reduced gasoline consumption and asignificant decrease of COoutput is only possible by using modern turbocharger tech-nology and fuel injection systems. The temperature in the housings will reach ca. 1050°C and it is necessary to use austenitic cast steel like 1.4848 for the housings. Drilling and threading are quite difficult technologies in this material.The experiment conducted by the authors showed, that for the machining of heat resistant cast stainless steel 1.4848 totally different drill designs are recommended from the precision tool manufactures. For a reduced or smaller axial force, cutting torque and a slower increase of the tool wear with an indication of longer tool life the following geometries does have positive aspects: a concave or straight cutting edge with a small cutting edge radius provides decrease in process parameters and a longer tool life. A reduction of the helix angle in combination with a straight nearly sharp cutting edge (small radius) provides also good results. Convex main cutting edges and high cutting edge radii or strong facets delivers higher forces and cutting torques in combination with a stronger corner edge wear. For a stabilization of the cutting corner edge, this part of the drill should be slightly rounded or produced with a small facet. A small land of the drill in combination with a step grinding gives advantages in comparison to wider lands with a continuous transition, due to reduced friction and a lower tendency of cold welding or build up edge.

Urbochargers are important components to minimize the petrol consumption of modern gasoline engines. The temperature in the turbocharger housings can reach until1.050 °C. Due to this reason, high heat resistant stainless steel, like the material DIN1.4848 with a high quantity of nickel (up to 25 %) and chrome (up to 20 %) is used in this application. During metal cutting operations the temperature at the cutting edge will increase due to the high quantity of nickel and the abrasive wear will be created by the chrome carbides within the cast material. The material hardness can increase by the machining process. Drilling and threading are one of the most critical machining operations in this material, because a huge frication area exists between the material and the tool. This provokes a high friction and the possibility of built-up-edge at the cutting edge which provides the rapid wear of the tool. In this part of the development project the tool life of different threading tools was analyzed. Taps in HSS-Co-PM and solid carbide were available for the tool life tests. The possibility to use the cold forming technology for threading was also analyzed. The strength of the internal threads was tested with pull out tests according DIN 898-2.

In the article the authors present the data of laboratory researches of geosynthetic grid samples based on polyamide-6, taken from the embankment slopes constructions of different light after 9 years of operation. The samples of geosynthetic grid EnkamatS20 were selected from the ground constructions of Svyataya Kanavka (Holy Groove) in the South of the Nizhny Novgorod region, the village of Diveevo, constructed in 2003 for the erosion preventive fixing of the slopes of the ditch and a shaft. The village of Diveevo is situated in a zone of clearly expressed continental climate, characterized by hot summers and cold winters. In the process of exploitation of ground structures in the period from 2003 to 2012, there was a decline in the protective properties of the lawn and turf, which was reflected in violation of the integrity of cover, including on the slopes of the ditch and of a shaft of a southern exposure, which are not sheltered from the direct streams of the sun. The similar situation was observed on deeply shaded slopes of a Northern exposure covered with trees and shrubs, as well as on the slopes of the bottom of the ditch, where the sun streams didn’t reach. From these mostly unprotected places in 2012 samples of geosynthetic grid Enkamat-S20 were selected in order to define the influence of the lighting conditions of slopes on the operational properties of Enkamat-S20 for 9 years of operation. According to the obtained data the residual tensile strength for each series of samples of geosynthetic grid Enkamat-S20 was identified. The influence of light intensity on the operational properties was evaluated by the highest residual tensile strength of the investigated samples compared to the passport strength value of geosynthetic grid Enkamat-S20. As a result of the research it was established, that the deeply shaded areas for 9 years of operation the reduction of tensile strength for samples of geosynthetic grid Enkamat-S20 amounted to 4.5 % and 6 % respectively. In the intensively lighted area the strength loss amounted to 39.5 % due to destruction of synthetic fiber. In the conditions of partial shadow the strength loss amounted to 25 %. As a result of the studies the authors offer the data on the lighting conditions impact on the operational properties of geosynthetic grid on the example of Enkamat-S20 upon condition disturbing the integrity of the lawn and turf, which are a natural protective shield.

In the last decades in a number of countries burned clays have been used as a pozzolanic additives to the concrete, which is connected with their universal distribution and cost savings due to reduction of long-distance transportation of the additives. The haydite dust is the co-product of the haydite gravel. At every enterprise of haydite gravel about 7-8 tons of haydite dust are daily formed. The haydite dust represents thermally activated clay. Its structure includes a certain amount of non-dehydrated clay and dehydrated clay minerals with crystal lattices of different levels of defects. Previously the authors described the compositions of cost-effective composite gypsum binding materials produced with complex mineral additive, including lime, a ground haudite dust and the superplasticizer possessing the durability at compression up to 27 MPa and coefficient of softening up to 0,78. In this paper the authors investigated the composition and structure of artificial stone on the basis of the developed composite gypsum binder. As a basic binder building plaster is used. In the research work the X-ray phase analysis, the differential thermal analysis, electron microscopy and the standard methods of research of concrete porosity were used. The introduction in composition of gypsum binder with a complex mineral additive allows to receive an artificial stone with more dense and finegrained structure, durability and water resistance in comparison with original binder without any additive. The content of ettringite in the course of hardening does not increase. The formation of low based low-main hydrosilicates of the calcium filling steam structure of a gypsum stone, forming additional contacts between the gypsum crystals, raising stone water resistance is established.

The paper presents the research of the process of recovery of used motor oil to be applicable for construction machinery. The solution to the problem in question consists in the development of compact oil recovery facilities to be installed in the areas where used oil is generated. Their concept of operation consists in the employment of baromembrane liquid separation principle. It is characterized by low power consumption, as the separation of used oil from admixtures may be performed within the temperature range of 20 to 40°C. The following conclusions were made upon completion of the research project:
used motor oils may be applied for recovery purposes through the application of membranes, with dimensions of pores varying from 0.15 to 0.5 mcm;
the optimal filtering pressure is to vary between 0.3 and 0.5 MPa;
any further research is to cover the problem of periodicity of maintenance of membranes aimed at the restoration of their performance and selectivity within a particular service period.
Depending on the type of membranes and the degree of used oil treatment, recovered oil may be applied for the initially designated purpose, as an additive injected into diesel fuel or delivered to major oil recovery facilities, although the latter purpose requires preliminary improvement of physical and chemical properties of used oil to assure its complete recovery.

The author argues that the current standards of the quality of discharged waste waters are the drivers of new technologies of their treatment. Now traditional biological treatment is considered a universal method. However, compliance with the most recent standards requires that efficient removal of phosphorus in the course of biological processes must rise from 20 - 40 % to 98 - 99 %, efficiency of treatment of ammonium must go up to 98 - 99 %, while the share of nitrate and nitrite compounds formed in the course of biological treatment must be limited.
Given the fact that the contemporary method of treatment of waste water must meet the ecological requirements and be economical, improved technologies of biological treatment are most acceptable ones.
For practical purposes, the most solicited technologies are those that are based on the alternation of aerobic and anaerobic conditions of treatment of waste waters and/or active sludge. The most widely spread aerobic - anaerobic technology of treatment employs the method of biological nitrification - de-nitrification, which is the only method of removing all nitrogen compounds (ammonium, nitrite, nitrate) in accordance with the regulations that are effective in our country.
Any accompanying microflora boosts the overall biomass, and the laminar structure of the biological film assures the simultaneity of both aerobic and anaerobic processes, and, therefore, it intensifies the process of treatment.
Application of chemical treatment is an essential constituent of the waste water treatment technology, as it assures in-depth removal of phosphorus.

Flow analysis and pressure loss in spiral chambers of turbines and pumps are considered in the paper. Drawbacks are also specified, and recommendations are provided in terms of the hydro-mechanical analysis and the construction of spiral chambers of combined pump-chamber units and centrifugal pumps.
Liquid flow pattern in spiral chambers of centrifugal pumps and combined pump-chamber units, when operating in the pump mode, has a diffuser character, and circulatory streams, flowing in opposite directions, evolve there; streams move clockwise in the bottom area of the cross section, and in the upper area, stream move counter clockwise (when directions of water flows inside chambers are considered).
The presence of circulatory streams and the diffuser nature of the flow inside spiral chambers of centrifugal pumps and combined pump-chamber units boost uneven distribution of velocities and the loss of pressure inside chambers and trail races.
The loss of energy (pressure) in spiral chambers and trail races of the above machines can be reduced, if the output section of the spiral has the shape of a torus with a central angle φ= 45….55, taken in-between the output section of the spiral and its tooth, while the cross sectional area is equal to the section area calculated as = const or ∙ = const (this section of the spiral is the initial section of the torus).

The problem of potential damage and destruction of constituent parts of hydraulic engineering structures, as well as deterioration of materials in the course of their continuous operation under the impact of natural and climatic factors is considered in the article. Practicability of development and implementation of the control system designated for the monitoring of the condition of hydraulic engineering structures and aimed at prevention of their destruction is under discussion. The authors insist that the safe operation of a hydraulic engineering structure, minimization of its maintenance costs and its negative impact on the environment depend on the step-by-step implementation of the aforementioned system.
Control over a hydraulic engineering facility should be based on advanced information systems capable of monitoring the structure condition in the non-stop mode. The systems should be efficient, reliable, cost-effective, computer-controlled, mobile and intelligent. Concepts of the two types of monitoring systems, an indicative and a representative one, are described in the article.

Methods and algorithms of control of the tension of lifting and towing ropes of bucket-chain excavators are proposed in the article. They are based on the non-linear dependence of the current path length and intensity of excavation efforts. Three automatic control modes, including scooping, correction signals and automatic overload protection, are implemented. Two independent control loops in charge of tension of lifting and towing ropes are developed.
The proposed automated control system may be integrated both into new bucket-chain excavators and into those excavators that are already in operation. The new system does not require any substantial alterations in electric drive control systems in charge of lifting and towing, if integrated into excavators in operation.
The author has performed the non-linearity analysis; he has also designed, developed and implemented the models that are capable of taking an adequate account of the system peculiarities identified in the course of the project implementation. The system parameters are adjustable to specific conditions of the excavator operation, including the hardness of the rock extracted by the excavator, etc.
The automatic overload control system attached to the electric drives in control of lifting and towing ensures maximal responsiveness of the system based on the commutation-related limitations imposed by power-driven elements, maximal over-control values and variability of the transition process.
Prevention of any rope slacks in the course of scooping of any hard rock is assured by the loop of regulation of minimal tension of lifting cables.
The service life of lifting and towing ropes goes up by eight to ten weeks, if the system proposed by the author is implemented.