Browsing by Author "Hubar, Oleksіy V."

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Comparative Analysis of Calculation Results of Supporting Structure of Soil-Cement Piles
(Kaunas University of Technology, Kaunas, 2019) Pshinko, Oleksandr M.; Petrenko, Volodymyr D.; Tiutkin, Oleksii L.; Andrieiev, Volodymyr S.; Hubar, Oleksіy V.; Ihnatenko, Dmytro Yu.; Markul, Ruslan V.
ENG: Abstract. The article presents the results of comparison of the stress-strain state of 4 models of a retaining wall structure of soil-cement piles on a landslide-prone slope. This study compares the changes in the stress distribution and displacements in the model elements of the retaining structure of soil-cement piles depending on the design parameters and the method of piles location in the body of the soil mass. The comparison of models of supporting structures of soil-cement piles on a landslide-prone slope allowed obtaining: –the comparative analysis of the quality work of individual elements of the supporting structure for strength and deformation in a three-dimensional representation; –the comparative assessment of the performance of the supporting structure of soil-cement piles on a landslide-prone slope; – histograms of dependences of changes in the angle of piles inclination to the vertical axis of their holding force, strength and deformation of the slope;
Comparative Analysis of the Results of Calculating the Stability of a Reinforced Subgrade with Geosynthetic Materials
(Kaunas University of Technology, 2021) Andrieiev, Volodymyr S.; Tiutkin, Oleksii L.; Hubar, Oleksіy V.; Markul, Ruslan V.
ENG: Тhе article presents the results of studies of the stress-strain state of the reinforced and unreinforced railway subgrade. Тhis study compares changes in the distribution of stresses and displacements in а railway subgrade. Comparisons of stresses and displacements made it ossible to obtain: - comparative analysis of the work of the main site of the subgrade under increased load with reinforcement and without reinforcement; - comparative assessment ofthe efficiency ofthe reinforced subgrade at increased load; - isolines and isofields of displacements and stresses in the body ofthe embankment at an increased load.
Features of the Nonlinear Calculation of the Stress-Strain State of the "Rock Massif–Excavation Support" System Taking into Account Destruction
(Kaunas University of Technology, Kaunas, Lithuania, 2019) Shashenko, Oleksandr; Shapoval, Volodymyr; Khalymendyk, Oleksii; Andrieiev, Volodymyr S.; Arbuzov, Maxim; Hubar, Oleksіy V.; Markul, Ruslan V.
ENG: The algorithm for estimating the reliability of the results of the calculation of the stress-strain state of the “rock massif-excavation support” system, taking into account the non-linear relationship between stresses and strains, as well as the destruction of the rock, is presented. In the course of a numerical experiment, it was shown that to determine the reliability of the calculation results, it is enough to find the relative error between the maximum efforts in the lining and then the extremum (more precisely, the maximum) of the “relative error – depth of the excavation center”.
The Influence of Geosyntetic Materials on the Strength in Uniaxial Compression of Soils of Railway Embasses
(Kaunas University of Technology, Kaunas, Lithuania, 2023) Andrieiev, Volodymyr S.; Tiutkin, Oleksii L.; Hubar, Oleksіy V.; Mukhina, Nataliya
ENG: Many specialists were engaged in ensuring the stability of the soils of the embankments of the railway track. Most of them propose to ensure the stability of embankments due to its reinforcement. There is a need to generalize and adapt individual features of different calculation methods in order to obtain a single calculation model of the system "embankment - reinforcing layer - base" and "base site - reinforcing layer - ballast layer". The operation of reinforcing layers depends on the type of soil, the type of reinforcing material, and the shape of the structure. Geotextile layers in embankments perform a reinforcing function. They are used to reinforce the embankment in order to increase the overall stability of the embankment and the local stability of the slopes. The reinforcing function is determined by the ability of the geotextile layer to improve the working conditions of the soil for displacement due to its perception of tensile forces, friction of the layer against the soil and changes in the stress state in the soil massif.
Investigation of the Operation of the Railway Track with Reinforced Concrete Sleepers in Curved Sections with Radius R ≤ 350 m
(Printing House “Technologija”, Kaunas, Lithuania, 2020) Markul, Ruslan V.; Hubar, Oleksіy V.; Arbuzov, Maxim; Andrieiev, Volodymyr S.; Tiutkin, Oleksii L.; Savyts’kyy, V.; Ganich, Ruslan Ph.
ENG: The article presents the results of the research on polygon extension for laying reinforced concrete sleepers under difficult conditions (R≤350 m, mountainous terrain) with ensuring safety traffic and reliable operation of the railway track. Changes in the geometry of the track in the plane with wooden sleepers and Д0 fastener as well as reinforced concrete sleepers with СКД65-Б fastener in the curve with the radius of 350 m were investigated. The results of the research allowed to obtain: - method and algorithm for determining the tapping section of the track gauge extension on reinforced concrete sleepers in curves with radius R ≤ 350 m; - comparative assessment of the track gauge change with the use of Д0 fastener (wooden sleepers) and СКД65-Б fastener (reinforced concrete sleepers) in curves with a radius R ≤ 350 m; - factors impact on the track gauge extension under difficult operating conditions; - empirical dependence of the process of the track gauge width change and the frequency of its adjustment in the cases of СКД65-Б fastener (reinforced concrete sleepers) and Д0 fastener (wooden sleepers) use in curves with radius R ≤ 350 m; - conclusions on the probability and feasibility of concrete sleepers use under mountainous terrain conditions, including difficult operating conditions (R ≤ 350 m).
Methods of Assessment of Ballast Contamination on Railways of Ukraine
(Technologija, Kaunas, 2022) Andrieiev, Volodymyr S.; Tiutkin, Oleksii L.; Hubar, Oleksіy V.; Markul, Ruslan V.; Mukhina, Nataliya
ENG: Ukrainian railways use a wide variety of methods for determining ballast contamination. Some regional branches of JSC "Ukrzaliznytsia" prefer to replace the old ballast with new instead of cleaning it. Others do the cleaning of crushed stone ballast. The periodicity of such crushed stone cleaning depends on local conditions and features of cargo transportation. Ballast contamination assessment plays an important role in this matter. The essence of the research is to reduce the time for obtaining results on the assessment of ballast contamination and to simplify it for use by one or two persons, who can act as track installers.
Research of Railway Crashed Stone Use of 40 –70 mm Fraction
(Kaunas University of Technology, 2018) Pshinko, Oleksandr M.; Patlasov, Oleksandr M.; Andrieiev, Volodymyr S.; Arbuzov, Maxim; Hubar, Oleksіy V.; Hromova, Olena V.; Marcul, Ruslan V.
ENG: The results of the conducted researches on operating, physical and mechanical properties of crushed stone of 40-70 mm fraction are presented in the article as well as the results of the comparison of the given fraction with the fraction of 25-60 mm and determination of the former fraction usage for the ballast with the purpose of more rational fund use during railway repair works. The conducted researches of 40-70 mm fraction of crushed stone allowed receiving: – actual values of technical indices of the product and adopted technical decisions; – conformity of the product with the operating conditions as well as physical and mechanical properties during track maintenance; – ability to perform tests; – comparison of physical, mechanical and operational properties of crushed stone of 40-70 mm fraction with the crushed stone of 25-60 mm fraction.
Results of the Analysis of Reinforcing Structures Performance when Strengthening Subgrade Slopes
(Printing House “Technologija”, Kaunas, Lithuania, 2024) Andrieiev, Volodymyr S.; Tiutkin, Oleksii L.; Hubar, Oleksіy V.; Mukhina, Nataliya
ENG: Recently, the issue of increasing the bearing capacity of the subgrade in operation has become particularly relevant. In this situation, the priority is to improve the methods of subgrade strengthening, which allow for the efficient design of the operated engineering structure without restricting traffic. The analysis of the performance of reinforcing structures when reinforcing subgrade slopes is performed using numerical modelling. The research task, which is solved in the course of numerical modelling, is to substantiate the methods of subgrade reinforcement used in the design of strengthening of operated embankments and to determine an effective scheme for strengthening the sloping parts of the subgrade.
Study of the Interaction of the Railway Track and the Rolling Stock Under Conditions of Accelerated Movement
(IOP Publishing, 2020) Hubar, Oleksіy V.; Markul, Ruslan V.; Tiutkin, Oleksii L.; Andrieiev, Volodymyr S.; Arbuzov, Maxim; Kovalchuk, O.
ENG: Comprehensive studies of the interaction of the railway track and the investigated rolling stock under accelerated conditions have been carried out. The basis of the research was to obtain and substantiate the process of stress state, force interaction of the railway track and the rolling stock under conditions of accelerated movement. Introduction of the new rolling stock into continuous operation is a serious task that must be solved comprehensively. The implementation of this direction significantly affects the reliability of the elements of the railway track. Within the framework of the research, the approach was used that takes into account theoretical and experimental parts of the research using the methodology of prof. O. P. Yershkov. As a result of the studies, average stress values were established: in rails, they variate within the range 44.37...70.99 MPa; in the sleeper, they reach 0.78 MPa; in the ballast layer, they have 0.13 MPa; in the body of the subgrade, they reach 0.04 MPa, which is significantly less than the maxima allowable values. While speed change from 140 to 160 km/h, the values of the studied parameters decrease: vertical force (9.39 %), lateral forces (19.79 %); stresses in the edge of the rail flange (15.86 %); stresses in the edge of the rail head (16.67 %); stresses in the neck of the rail (8.74 %). The obtained results made it possible to form trends and recommendations on the feasibility of further increasing speeds development. At the same time, this made it possible to substantiate in more detail the operation of the railway track in the case of accelerated movement.