Izvestiâ Peterburgskogo universiteta putej soobŝeniâ最新文献

{"title":"The Incremental Launching Method with a Floating Support of Metal Combined Bridge Superstructures","authors":"Pavel Tatarenko, Sergey Chizhov, Yuliya Avdey, Anatoliy Antonyuk","doi":"10.20295/1815-588x-2023-3-685-693","DOIUrl":"https://doi.org/10.20295/1815-588x-2023-3-685-693","url":null,"abstract":"Purpose: To consider the necessity of applying the erection technology of metal combined superstructure in the form of a lattice truss with a triangular lattice and a rigid bottom chord with driving underneath single span bridges by the incremental launching method with the use of floating support. To show the significance and efficiency of this method. To give the sequence of the main installation operations. To draw a general scheme of launching. To outline the procedure for checking the superstructure at all stages of erection. To show the method of checking the floating support according to two groups of limit states. Methods: Comparison of incremental launching using a floating support with incremental launching using auxiliary supports, as well as construction of the span on falsework. Analysis of the stress values obtained during the inspection of the superstructure at all stages of erection, as well as of the analytical expressions of the floating support inspection methodology. Results: The advantages of the incremental launching with the use of floating support in comparison with other types of installation of metal combined superstructure are specified. The main operations and features of metal combined superstructure erection are outlined. The general scheme of installation of facilities is given on the example of construction of the highway bridge over the river Psezuapse, as well as comments on the verification of the metal combined superstructure are given. The basic formulas for checking the floating support are expressed. Practical significance: Features and advantages of this method of installation of metal combined superstructure will simplify the construction of single-span bridges with the superstructure of this kind, as well as increase the economic efficiency of such projects. The method of floating support testing can be recommended for practical use.","PeriodicalId":476051,"journal":{"name":"Izvestiâ Peterburgskogo universiteta putej soobŝeniâ","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136130117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrological Conditions for the Formation of Phytocenoses on Reclaimed Colliery Spoil Heaps","authors":"Alina Harlamova, Aleksandr Haritonenko, Valentina Solov'eva, Ol'ga Suvorova","doi":"10.20295/1815-588x-2023-3-751-757","DOIUrl":"https://doi.org/10.20295/1815-588x-2023-3-751-757","url":null,"abstract":"Purpose: Study of the hydrological conditions for the formation of phytocenoses on reclaimed colliery spoil heaps. The state of the formed phytocenosis on the surface of the reclaimed colliery spoil heap has been studied. Experiments have been carried out in field conditions to determine the permeability of the spoil material of the reclaimed spoil heap. The influence of hydrological conditions on the formation of phytocenoses in quasinatural landscapes is analyzed. Methods: Analysis of the state of the phytocenosis of the reclaimed spoil heap with the determination of the water permeability of the spoil material. Results: It has been established that the productivity of phytocenoses on reclaimed spoil heaps of coal mines directly depends on the hydrological properties of the formed soils, and is more effective in areas where the process of soil formation is almost completed. Practical significance: It is shown that the most favorable hydrological conditions on the surface of the reclaimed colliery spoil heaps contribute to the formation of phytocenoses at the level of natural landscapes.","PeriodicalId":476051,"journal":{"name":"Izvestiâ Peterburgskogo universiteta putej soobŝeniâ","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136130126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of the Impact of Wheel Dynamic Load on Rails under High-Speed Train Operations in Uzbekistan","authors":"Saidburhan Dzhabbarov, Nodirbek Kodirov","doi":"10.20295/1815-588x-2023-3-531-543","DOIUrl":"https://doi.org/10.20295/1815-588x-2023-3-531-543","url":null,"abstract":"Purpose: Justification of choosing the factors influencing the formation of dynamic load on the railway track by modern rolling stock during high-speed and very high-speed operations. To achieve this goal, theoretical groundwork and experimental research have been conducted. As a result of the work, a methodology has been developed for determining the vertical calculated force exerted by the wheel on the rail. Methods: High-speed and very high-speed trains, due to their fundamental design and significant increase in speed, necessitate a reconsideration of methods for calculating the impact of rolling stock on the railway track. This includes the analysis of relationships between root-mean-square deviations of various dynamic forces and the assessment of the influence of different factors at different speeds of operation. Results: As part of the study, experimental measurements have been conducted to examine changes in dynamic load. As a result, dependencies between the average and calculated vertical forces and the speed of operation for modern passenger trains have been obtained. By using factorial analysis of variance, numerical characteristics of the influence of various factors on the value of the vertical force exerted by the wheel on the rail have been obtained. Additionally, the degrees of influence of different factors on the formation of this force have been determined.","PeriodicalId":476051,"journal":{"name":"Izvestiâ Peterburgskogo universiteta putej soobŝeniâ","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136130127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Greenhouse Gas Emissions in BRICS and Ways to Reduce Emissions from Rail Transport","authors":"Rasul Ahtyamov, Elena Makarova, Alina Gavrilova","doi":"10.20295/1815-588x-2023-3-694-705","DOIUrl":"https://doi.org/10.20295/1815-588x-2023-3-694-705","url":null,"abstract":"Purpose: To analyze greenhouse gas emissions from the BRICS countries, as well as ways to reduce emissions from rail transport. Methods: The contribution of the BRICS countries to global greenhouse gas emissions based on an array of statistical data for the period from 1990 to 2019 has been estimated. The value of CO2 emissions per unit of energy produced in the BRICS countries from 1965 to 2021, as well as the sources of CO2 emissions, have been determined. Results: It is shown that the most effective way to combat climate change is to directly reduce emissions. In general, the emissions of the railway industry depend on the level of electrification. However, when assessing not only direct but also indirect emissions, the energy source and its carbon footprint become of primary importance. The development of intermodal transportation in BRICS countries is significant because these routes have the potential to reduce emissions. Carbon regulation leads to a redistribution in the sphere of international freight transportation among BRICS countries. Competitive advantages are increasingly evident in the railway transportation sector. However, this effect depends on the measures taken to adapt to changes in the transportation market by other modes of transportation. Practical significance: Ways to improve the sustainability of transport infrastructure have been formulated. The lowcarbon transport industry in the BRICS countries can be seen as an important component in reducing gross greenhouse gas emissions given the current high level of reliance on fossil carbon fuels and the inertia driven by the long life of fossil fuel infrastructure. Without the use of negative emission technologies, the required costs for reducing greenhouse gas emissions can be 40 % higher than with the use of negative emission technologies. As part of the reduction of greenhouse gas emissions by railway transport facilities in the BRICS countries, the following measures can be implemented: direct reduction of greenhouse gas emissions; introduction and implementation of technologies for negative emissions at railway transport facilities, taking into account their geospatial distribution and their specific characteristics; attracting investments and ensuring access to more affordable financing for these projects; integration of climate change mitigation issues into the strategies of transportation companies; further electrification in transportation and transitioning to alternative fuel sources; utilization of digital technologies to optimize transportation systems and reduce the environmental impact of the railway industry.","PeriodicalId":476051,"journal":{"name":"Izvestiâ Peterburgskogo universiteta putej soobŝeniâ","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136130255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forecasting Ultimate Tensile Strength and Elastic Modulus Values of Large-Diameter Composite Rebar Using Indirect Indicators","authors":"Ekaterina Bogdanova, Andrey Benin","doi":"10.20295/1815-588x-2023-3-673-684","DOIUrl":"https://doi.org/10.20295/1815-588x-2023-3-673-684","url":null,"abstract":"Purpose: To consider the problems of experimental determination of elastic and strength properties of largediameter composite polymer glass fiber reinforced plastic rebar (FRP-rebar). To analyze the state of the issue, to make an overview of existing methods for determining elastic and strength properties of FRP-rebar. To show the necessity of developing methods of predicting the large-diameter FBR-rebar elastic and strength properties by means of indirect measurement methods. To carry out a series of tensile tests of FRP-rebar and to calculate the elastic-strength characteristics values using the rule of mixtures for composite materials. To make a comparative study of data obtained by experimental and analytical methods. Methods: Comparative analysis of the FRP-rebar elastic-strength characteristics calculated values with experimental data. Results: The need to improve the existing regulatory method for determining the elastic-strength characteristics of composite reinforcement bars is indicated. Calculation formulas of analytical prediction of the ultimate tensile strength and elastic modulus of FRP-rebar have been established. The calculated values obtained have been verified. The need of additional tests to build a statistical database has been identified. Practical significance: The proposed method for indirect measurement of FBR-rebar properties can be recommended for further experimental testing to reduce the risk of obtaining error values of elastic and strength characteristics of largediameter FRP-rebar when conducting direct experiments.","PeriodicalId":476051,"journal":{"name":"Izvestiâ Peterburgskogo universiteta putej soobŝeniâ","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136130258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sector Plate Bending: Using Computer Algebra Systems","authors":"Dmitriy Goloskokov, Aleksandr Matrosov","doi":"10.20295/1815-588x-2023-2-376-384","DOIUrl":"https://doi.org/10.20295/1815-588x-2023-2-376-384","url":null,"abstract":"Purpose: To investigate the stress-strain state of a thin homogeneous isotropic plate in the form of a sector by numerical-analytical method. To consider the possibility of using computer algebra systems (CAS) to calculate sectoral plates operating under bending due to a transverse load. To demonstrate the effectiveness of applying one of these CASs through the example of the Maple system for calculations using the Ritz method — performing analytical transformations when calculating the integral that determines the total potential energy functional, forming and solving the main resolving system of linear algebraic equations with respect to unknown numerical coefficients in the formula approximating the deflection of the plate, visualization of the obtained solution. Methods: A direct method is used to solve the variational problem of minimizing the functional of the total potential energy of deformation of a thin homogeneous isotropic plate in the form of a sector — the Ritz method. The solution is constructed in the form of a series in terms of basis functions. As basis functions, polynomial functions are chosen that exactly satisfy all boundary conditions. Results: An approximate numerical-analytical solution has been obtained for the problem of bending a sectoral plate in the form of a quarter of a circle, clamped along the contour and loaded with a uniformly distributed load. The effectiveness of using the Maple analytical computing system for solving the problem of bending a sectoral plate by the variational Ritz method is demonstrated. It is shown that the resulting solution quickly converges both for deflection and for bending moments and stresses. Practical significance: The algorithm proposed in the article for solving the problems of bending sectoral plates can be recommended for practical use in determining the stress-strain state of such plates.","PeriodicalId":476051,"journal":{"name":"Izvestiâ Peterburgskogo universiteta putej soobŝeniâ","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135187318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ecological Assessment of Environmental Objects During Engineering and Environmental Surveys","authors":"Natal'ya Gorbunova, Anastasiya Fedoseenko, Mahmud Abu-Hasan","doi":"10.20295/1815-588x-2023-2-441-447","DOIUrl":"https://doi.org/10.20295/1815-588x-2023-2-441-447","url":null,"abstract":"Purpose: To assess the current ecological condition of the survey site located in the Republic of Karelia and intended for laying a non-public railway track. To analyze the component of the environment — the soil, for compliance with the requirements of regulatory documentation. To establish the category of soil pollution in accordance with Sanitary and Epidemiological Standards and Regulations SanPiN 2.1.3684 and the rules for further use in accordance with SanPiN 2.1.3685. Methods: To assess the degree of soil contamination with heavy metals and organic ecotoxicants, samples have been taken from 14 test sites. Assessment of the degree of soil contamination with heavy metals and benz(a)pyrene has been carried out in accordance with SanPiN 1.2.3685. The assessment of the degree of contamination of soils with petroleum products has been carried out in accordance with a letter from the Ministry of Natural Resources and Environment of the Russian Federation. The assessment of the danger of soil pollution has been carried out according to several indicators (Tables 4.3–4.5 of SanPiN 2.1.3685): 
 –- a complex of metals for public health is made according to the indicator of total pollution (Zc); 
 –- the presence/absence of excess over the established maximum permissible concentrations (MPC) and approximately permissible concentrations (APC). The pollution category is determined by the worst indicator. When establishing pollution categories worse than “permissible”, recommendations have been developed for the further use of contaminated soils (Appendix No. 9 to SanPiN 2.1.3684). Results: As a result of the tests conducted, it was determined that the soil samples collected from the survey area for the construction of a non-public railway section comply with the soil pollution category of “Permissible” and, according to the rules of further usage, fall under the classification of “Unrestricted Use”. Practical Significance: The investigated soils meet all the requirements of the regulatory documentation and can be used without restrictions for the construction of the non-public railway section.","PeriodicalId":476051,"journal":{"name":"Izvestiâ Peterburgskogo universiteta putej soobŝeniâ","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135187319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation of Electric Braking Mode of a Diesel Locomotive with Series Excitation of Commutator Traction Motors Using a Power Semiconductor Converter","authors":"Vyacheslav Evseev, Anatoliy Savos'kin","doi":"10.20295/1815-588x-2023-2-463-470","DOIUrl":"https://doi.org/10.20295/1815-588x-2023-2-463-470","url":null,"abstract":"Purpose: To consider the structure, advantages and operating principle of a new transistor converter based on isolated gate bipolar transistors (IGBT) for diesel locomotives with commutator traction motors in the electric braking mode, as well as the implementation features of this mode on diesel locomotives. To show the functional structure of the converter automatic control system for the electric braking mode. To plot a potential braking characteristic of a diesel locomotive with a new converter. Methods: Simulation modeling of the electric braking mode using a computational mathematical model of a traction drive in the Matlab Simulink environment. Analysis of the simulation results of the traction drive operation in stationary and dynamic conditions. Comparison of the obtained braking characteristic with the existing one for 2TE25KM diesel locomotive. Results: It is established that the use of the proposed transistor traction converter in the power electrical circuit of a diesel locomotive provides axis-by-axis control of a commutator traction electric drive in the electric braking mode with series excitation of traction motors and allows to significantly increase the electric brake efficiency at low speeds. The proposed solution implements the target braking force of the locomotive in a wide range of speeds, as well as its limitations due to the electromechanical parameters of the diesel locomotive assemblies. Practical significance: It is shown that the proposed solution provides the increase of the electric brake efficiency, life extension of brake shoes and wheels of the rolling stock.","PeriodicalId":476051,"journal":{"name":"Izvestiâ Peterburgskogo universiteta putej soobŝeniâ","volume":"276 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135187317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}