Випуск 27 (МТ)

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ENG: Issue 27 (BT)

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Dependence of the Stress-Strain State of the Metro Running Tunnel Lining on its Shape
(Український державний університет науки і технологій, Дніпро, 2025) Wu, Haoshuai; Bannikov, Dmytro O.; Kuprii, Volodymyr; Wu, Zheye
ENG: Purpose. The purpose of the scientific article is to conduct a numerical analysis of the metro running tunnel to determine, based on the results, the dependence of the lining's stress-strain state on its shape. To achieve this goal, a modeling of a tunnel with a circular outline and an ovoid shape was performed. Methodology. LIRA-CAD is a multifunctional software package for calculation, research and design of structures for various purposes. It is based on the use of the finite element method (FEM), recognized worldwide as the main tool for numerical analysis of the building structures’ strength and stability. Calculation of forces, modeling of changes in the stress-strain state of the structure at the stages of its construction and research of the operation of building structures using the finite element method are performed after specifying the materials and properties of the elements. Findings. Finite element models of the soil massif and tunnel linings of various shapes (circular outline and ovoid shape) were developed for numerical analysis of the system. An analysis of the results of the stress-strain state of the soil massif and tunnel linings was performed, which allowed to draw a conclusion about the discrepancy of the results for different lining shapes. The analysis was conducted for the stress-strain state of linings of various shapes, taking into account the method of construction and their waterproofing, allowing to conclude that ovoid linings, which are constructed by NATM, have advantages in strength and durability. Originality. The originality of the scientific research lies in the analysis of the stress-strain state of the metro running tunnel lining in various engineering and geological conditions, which provides an opportunity to reasonably use calculation methods, the results of which reflect the most reliable operation of the structure for specific engineering and geological conditions. Practical value. The practical value lies in the fact that the developed methodology allows for considering underground structures of complex spatial forms, various models of soil behavior, taking into account the technology of tunnel construction.
Analytical Regularities of Force Factors in the Lining of a Three-Vaulted Metro Station with Variation of the Elastic Resistance Coefficient of the Rock
(Український державний університет науки і технологій, Дніпро, 2025) Jiang, Congying; Tiutkin, Oleksii L.; Chen, Zehui; Chen, Zhixiang
ENG: Purpose. The purpose of the scientific article is to conduct a numerical analysis of pylon station models and obtain force factors for its lining. Based on the obtained factors (bending moments and normal forces), it is planned to obtain their analytical regularities for the varying elastic resistance coefficient of the rock. Methodology. The calculation scheme of the station structure should be chosen so that it corresponds to the real operating conditions of the lining to the greatest extent, reflecting the design features, lining material, geological conditions, and the construction method. The SCAD calculation software was used to calculate the pylon-type station. Findings. The foundations of mathematical modeling of a pylon station by the finite element method in a spatial setting were developed using the modified Metrodiprotrans method (based on FEM), models calculations for pylon deep metro stations were carried out by determining the parameters of equivalent bars in a spatial setting. Using the results of the regularities between the strength coefficient and the deformation characteristics of the soil (deformation modulus and Poisson's ratio), analytical regularities of force factors were determined for varying properties of the surrounding massif (elastic resistance), which for moments are power nonlinear regularities, and for normal forces are linear functions, furthermore the change in the elastic resistance coefficient with respect to the strength coefficient is a nonlinear polynomial. Originality. The originality of the conducted research lies in obtaining analytical regularities of force factors for varying properties of the surrounding massif based on the results of numerical analysis conducted on the basis of the finite element method using the modified Metrodiprotrans method. These regularities allow predicting the change in bending moments and normal forces depending on the change in geological conditions at the design stage. Practical value. The practical value of the research lies in developing the basics of the methodology for taking into account the spatial factor in the calculations of three-vaulted metro stations. This allows for more complete consideration of the complex irregular structure of pylon-type stations and obtaining force parameters in its lining that are more adequate to the real situation.
Analysis of Modes and Frequencies of Natural Vibrations and Dynamic Stresses of Bridge Abutment Foundation and Soil Base
(Український державний університет науки і технологій, Дніпро, 2025) Radkevych, Anatolii V.; Dubinchyk, Olha I.; Hu, Zuolin; Kozak, Bohdan Yu.
ENG: Purpose. The purpose of the research work is to determine, during the modal analysis, the modes and frequencies of natural vibrations of the railway bridge abutment together with the pile cap and pile foundation. A separate task of the research is to clarify the dynamic influence of the abutment structure on the possibility of vibrational displacements of the soil base. Methodology. To calculate the pile foundation of the abutment, which interacts with the surrounding massif, it was decided to use the finite element method (FEM) based on Structure CAD for Windows, version 7.31 R.4 (SCAD). To reproduce the features of the pile foundation of the abutment, a flat (quasi-spatial) model was used in the research. All dimensions of the pile cap and piles are adopted according to the design documentation for the construction of an actual overpass. Findings. An analysis of the stress-strain state results of the overpass abutment foundations, taking into account the train load, was performed, which made it possible to obtain a conclusion about the high bearing capacity of all parts of the “pile – pile cap” system for all considered types of load combinations with a safety margin of 8 and 7 times, respectively, which indicates normal operation in the future provided an unchanged state of engineering and geological conditions and loads. The pile material, class C30/35 concrete, fully withstands all types of loads represented by load combinations, taking into account the dynamic coefficient. The modal analysis of the overpass abutment foundations shows that the obtained frequencies and modes for the foundation are equal to 2.5 Hz (fundamental tone) … 6.6 Hz, and from comparing these frequencies with the liquefaction frequencies of wet sands (30 … 50 Hz) it is clear that the support's own vibrations cannot cause vibration-induced liquefaction. Originality. The originality of the conducted research lies in obtaining the parameters of dynamic displacements and natural vibration frequencies during the modal analysis of a railway bridge abutment Practical value. The practical value lies in substantiating the strength of the abutment structure under varying load combinations, as well as in determining that the dynamic impact of the rolling stock does not affect the vibrational displacements of the foundation soils.
Assessment of the Impact of Operating Conditions on the Reliability of Bar-Type Steel Structures
(Український державний університет науки і технологій, Дніпро, 2025) Ivanova, Hanna; Radkevych, Anatolii V.; Olishevska, Sofiia; Tianwei, Ma
ENG: Purpose. The study aims to develop a comprehensive approach to calculating the residual service life of spatial multi-element steel bar structures, taking into account both predictable and random factors that affect the structures or their individual elements throughout their service life. Methodology. The key causes of corrosion damage are examined, and models of corrosion wear are analyzed, including those that consider the effects of mechanical stresses and aggressive environments. The use of different types of survivability indicators – both deterministic and stochastic – allows for a more accurate assessment of structural reliability under real operating conditions. It is noted that current construction standards insufficiently account for the time-dependent development of defects, which complicates the assessment of the residual service life of structures. The need for a comprehensive approach to forecasting the reliability and durability of steel structures in actual service conditions is emphasized. Findings. It is demonstrated that traditional calculation methods do not adequately assess the durability and survivability of structures with evolving defects. An approach to evaluating the survivability of steel structures is proposed, based on the use of both deterministic and stochastic indicators. This allows for consideration of both systematic and random changes in the behavior of the structural system. The advantage of mathematical modeling over physical modeling is substantiated, particularly in its ability to account for multiple scenarios of corrosion development and the complex interaction of corrosion with mechanical influences. Parameters characterizing the condition of a structure under corrosion wear have been identified. Originality. A comprehensive approach to assessing the reliability and survivability of bar-type steel structures under corrosion wear has been developed, based on a combination of deterministic and stochastic indicators. Mathematical models of corrosion damage are considered, taking into account the influence of both stress–strain state and aggressive environments. Practical value. The obtained results can be used in the design, diagnostics, and forecasting of the technical condition of bar-type steel structures operating in aggressive environments and exposed to various types of loads.
Пам’яті професора Володимира Дмитровича Петренка
(Український державний університет науки і технологій, Дніпро, 2025) Тютькін, Олексій Леонідович
UKR: Стаття присвячена пам’яті видатного вченого в області буровибухових робітпрофесора Володимира Дмитровича Петренка.
Justification of Capital Repair of a Highway Bridge When Changing the Load
(Український державний університет науки і технологій, Дніпро, 2025) Miroshnyk, Vitalii; Tao, Mingzhu; Du, Xuanchen; Ivanchenko, V. S.
ENG: Purpose. The purpose of the scientific article is to substantiate the implementation of capital repairs of a road bridge that has been significantly damaged as a result of hostilities. The achievement of this goal is based on numerical analysis of the model using the finite element method, taking into account recommendations for reinforcing bridge elements. Methodology. Loads and impacts gathered during numerical analysis ensure the verification of bridge structures and elements for strength, stability, and durability according to the first group of limit states criteria, as well as stiffness and crack resistance according to the second group of limit states criteria. Temporary loads and impacts for structures calculating for all groups of limit states are taken with reliability factors for loads γf and dynamics factors (1+µ). The structure utilizes standard I-section beams for the superstructure with lengths of 22.16 m and 32.96 m, designed according to the working drawings and calculations developed by "International Design Institute" LLC and modeled in the professional structural analysis software Lira-CAD. Findings. The calculation of the beams was performed in two stages, reflecting their work: Stage 1 – Concreting the slab, the slab is not included in the structural analysis; Stage 2 – The slab is included in the span work, concreting of sidewalks without inclusion in the structural analysis, laying of asphalt concrete pavement, barrier railing, guardrails and expansion joints. The structure of the temperature-continuous monolithic slab, calculated using the Lira-CAD structural analysis software, has been reinforced considering the entire range of loads. Originality. The originality of the study lies in the scientific substantiation of carrying out major repairs on the bridge, which provides the possibility of the passage of temporary vertical loads according to H-30 and NK-80 schemes and pedestrian load on the sidewalks. Practical value. The practical value lies in the justification of the works on the restoration of the bridge design characteristics. Moreover, the calculations of the loads and impacts provide verification of the structures and elements of the bridge as well as the sequence of work operations during construction.
Numerical Analysis of a Single-Vaulted Metro Station Options
(Український державний університет науки і технологій, Дніпро, 2025) Smolianiuk, N. V.; Bielikova, Sofiia; Zhang, Qianhui; Zhu, Yibiao
ENG: Purpose. The purpose of the study is a numerical analysis of a single-vaulted metro station options, the performing of which allows determining which of the options passes the strength check. The results of the numerical analysis using the finite element method, which allows to determine the strength of the station structure, are the values of the stress-strain state, as well as equivalent stresses. Methodology. An analysis of the lining stress-strain state for variating structural solutions was carried out, for which the model reproduced half of the single-vault station structure with the addition of a second invert. The single-vault station models were built based on real geometric dimensions using the professional calculation software Structure CAD for Windows, version 7.29 R.3 (SCAD). Findings. In recent years, the single-vaulted metro station has become the underground structure most often used during construction. The design options for the single-vaulted station proposed by designers necessarily require scientific substantiation. As part of the study, the results of which are presented in the article, a numerical analysis of the single-vaulted station, which has two design options, was performed. The created finite element models reflect the features of the developed options in a spatial setting. The numerical analysis performed for dead weight and moving load allowed for finding out the parameters of the stress-strain state. Based on the determined parameters, the overall strength and stability of the single-vaulted station were evaluated and recommendations for their increase were provided. Originality. The originality of the study consists of the obtained results of numerical analysis for a single-vaulted metro station options, which allowed to find out which of the options passed the strength check. Practical value. The practical value lies in obtaining the results of the calculation using the finite element method, which allowed to find the strength of the station structure and reasonably choose the metro station option.
Analysis of the Impact of the Construction Technology of a Column-Type Metro Station on the Stress-Strain State of its Structure
(Український державний університет науки і технологій, Дніпро, 2025) Kuprii, Volodymyr; Chen, Baochun; Wang, Dongdong; Honchar, S. V.
ENG: Purpose. The purpose of the scientific research is to analyze the influence of the construction technology of the metro column station on the stress-strain state of its structure. The achievement of this goal is based on the numerical analysis of the metro column station, during which the construction stages of the underground facility are taken into account. Methodology. To calculate the stress-strain state of the column-type station structure at different stages of the station lining construction, the modern LIRA-CAD calculation complex was used. Eight stages of the station construction were considered, for which finite element models were developed. After creating finite element models for the eight stages of the column station construction, a numerical analysis was performed. Findings. The main results of the work demonstrate that the correctly selected construction technology is critically important for ensuring the stability of the station structures and minimizing the risks of deformations in the soil. The study considers the stages modeling of the station construction using the LIRA-CAD software package. Thanks to this, accurate data on the structural performance of the structure at different stages of construction were obtained. The results obtained allow to state that the proposed construction technology provides high reliability and durability of the column station, and also minimizes the negative impact on the rock massif. This is confirmed by low settlement values and uniform stress distribution in the structure. Moreover, the proposed safety measures and recommendations for monitoring the condition of structures can be used to increase the efficiency of the station operation in the future. Originality. The originality lies in the fact that the analysis of the results showed that the greatest stresses occur in the connection zones of the central and side tunnels, which requires special attention to the design and construction of columns and lining of the station. Practical value. The practical value lies in the fact that the developed recommendations for strengthening stressed zones allow to significantly increase the safety of operation.
Numerical and Modal Analysis of the Railway Bridge Pier
(Український державний університет науки і технологій, Дніпро, 2025) Tiutkin, Oleksii L.; Dubinchyk, Olha I.; Zhang, Quan; Du, Kaiqian
ENG: Purpose. The purpose of the scientific research is to conduct numerical and modal analyses of the railway bridge pier with a variation of load combinations and to determine the strength parameters and dynamic characteristics (shape and frequency of natural vibrations). Methodology. Pile foundations are the most economical and effective for bridge construction. In this case, the pile foundation of the overpass pier is constructed on bored piles. To reproduce the features of the pier’s pile foundation, a spatial FE-model was used, which most accurately reflects its interaction with the surrounding massif. Findings. An analysis of the results of the stress-strain state of the overpass pier foundation was performed, taking into account the train load, which made it possible to obtain a conclusion about the high bearing capacity of all parts of the “pile – pile cap” system for all considered types of combinations with a safety margin of 8 and 7 times, respectively, which indicates normal operation in the future provided an unchanged state of engineering and geological conditions and loads. The connection point of the piles and the pile cap, made of concrete class C25/30, fully withstands all types of loads presented in the combinations. A modal analysis of the foundations of the overpass pier models was performed and the frequencies and shapes of the foundation were obtained, which are equal to 4.2 Hz (main tone) … 17.4 Hz, and from comparing these frequencies with the liquefaction frequencies of wet sands (30 … 50 Hz) it is clear that the support's own vibrations cannot cause vibration liquefaction. Originality. The originality of the study lies in obtaining the values of the stresses of the overpass pier in the static formulation, as well as the dynamic characteristics (shape and frequency of natural vibrations) in the dynamic formulation. Practical value. The practical value lies in the substantiated assessment of the values of the pier’s vibration frequencies, which is based on the results of modal analysis and indicates the absence of sand liquefaction.