BİR DEMİRYOLU HATTININ BİRİM ESNEME DİRENCİ ÜZERİNDE ETKİSİ OLAN MEKANİK VE GEOMETRİK NİTELİKLERİN İNCELENMESİ

Abstract

Bir demiryolu hattının esneme direnci, hat tasarımında göz önünde bulundurulması gereken en önemli parametrelerden biridir. Bu değerin optimum değerinden düşük olması hattaki oturmaları artırırken, yüksek olması zaman içerisinde hat elemanlarında yıpranmalara neden olur. Bununla birlikte, hat esneme direncinin hat boyunca değişmesiyle dinamik darbe kuvvetleri artarak hattın bozulma sürecini hızlandırır. Hat esneme direnci; hattı oluşturan malzeme özelliklerine, zemin tabakasındaki yerel farklılıklara, hattaki bazı özel durumlara ve hat bileşenlerinin geometrisine bağlı olarak değişmektedir. Aynı zamanda araç-hat etkileşimi de hattın teker kuvvetine karşı gösterdiği tepkiyi etkilemektedir. Bu çalışma, demiryolu hat tasarımlarında esas alınacak olan hat esneme direncini tartışan temel bir kaynak olmayı hedeflemektedir. Bu anlamda yapı-zemin etkileşimini inceleyerek, taşıyıcı zeminin yanı sıra hat üstyapısına ait mekanik ve geometrik özelliklerin, hat ve zeminin bir bütün olarak düşey yükler altındaki tepkisini etkilediğini elastisite teorisine dayalı modeller üzerinden göstermektedir. Daha sonra, araç-hat etkileşimi ele alınmış ve hatta ait tüm parametreler aynı kalsa dahi sadece dingil mesafesindeki değişim nedeniyle hat tepkisinin değiştiği gösterilmiştir. Son olarak, hatta ait mekanik ve geometrik niteliklerin eşdeğer hat esneme direnci üzerindeki etkileri açıklanmıştır.

Keywords

• Hat esneme direnci
• Hat modülü
• Yatak Modülü
• Hat Üstyapısı
• Araç-Hat Etkileşimi

INVESTIGATION OF THE MECHANICAL AND GEOMETRIC PROPERTIES AFFECTING THE RAILWAY TRACK STIFFNESS

Abstract

Track stiffness is one of the most important parameters to be considered in track design. While track stiffness is lower than an optimum value, excessive track displacement occurs, and while it is higher than the optimum, it can cause the deterioration of the track and the components of the track in time. Variation of the track stiffness can increase dynamic impact forces and thus, accelerates the track deterioration. Track stiffness depends on the material properties that constitute track, the local differences in the soil layer, some special conditions, and the geometry of the track components. Also, the track-train interaction affects the reaction of the track against the wheel force. This study aims to be a fundamental resource discussing the track stiffness that will be taken as a basis in railway track design. In this sense, the study shows that the mechanical and geometric properties of the track superstructure affect the common response of the track and soil under the wheel forces by examining soil-structure interaction through elasticity theory-based models. Later, the train-track interaction is discussed and it is shown that even if all parameters of the track remain the same, the track response can change with the axle spacing. Finally, the effects of the mechanical and geometric properties of the track on the equivalent track stiffness are explained.

Keywords

• Track stiffness
• Track modulus
• Subgrade reaction
• Track superstructure
• Train-track interaction

References

1. Anbazhagan, P., Indraratna, B., Rujikiatkamjorn, C., Su, L. 2010. Using a seismic survey to measure the shear modulus of clean and fouled ballast. Geomechanics and Geoengineering: An International Journal, 5(2), 117-126.
2. Balcı, E., 2021. Ray Pedi ve Travers Altı Pedlerin Hat Bileşenleri ve Hat Performansı Üzerindeki Etkileri. Demiryolu Mühendisliği, 13, 14-28.
3. Balcı, E., Bezgin, N. Ö., 2020. Hat esneme direncinin hat performansı üzerindeki etkileri. Demiryolu Mühendisliği, 11, pp. 75–85.
4. Balcı, E., Bezgin, N. Ö., Wehbi, M., 2021. Investigation of Variation of Track Response to Wheel Forces with Bogie Axle Spacing and Introduction of the Concept of Effective Track Stiffness. Transportation Research Record (In-Review).
5. Berggren, E., 2009. Railway track stiffness. Dynamic measurements and evaluation for efficient maintenance. Ph.D. dissertation, KTH Royal Institute of Technology, Stockholm
6. Bezgin, N. Ö. 2017. Development of a New and an Explicit Analytical Equation that Estimates the Vertical Dynamic Impact Loads of a Moving Train. Procedia Engineering, 189, 2–10.
7. Bezgin, N. Ö., & Wehbi, M. 2019. Advancement and Application of the Bezgin Method to Estimate Effects of Stiffness Variations along Railways on Wheel Forces. Transportation Research Record: Journal of the Transportation Research Board, 036119811983580.
8. Burrow, M., Teixeira, P.F., Dahlberg, T., Berggren, E. 2009. Track stiffness considerations for high speed railway lines. Railway transportation: policies, technology and perspectives, pp. 303-354.

9. Dahlberg, T., 2010. Railway Track Stiffness Variations Consequences and Countermeasures. International Journal of Civil Engineering, Vol 8, No 1.
10. Grossoni, I., Bezin, Y., Neves, S. 2018. Optimisation of support stiffness at railway crossings. Vehicle System Dynamics, 56(7), 1072-1096.
11. Grossoni, I., Hughes, P., Bezin, Y., Bevan, A., Jaiswal, J., 2020. Observed Failures at Railway Turnouts: Failure Analysis, Possible Causes and Links to Current and Future Research. Engineering Failure Analysis Vol. 119.
12. Gürmak Demiryolu, “W21 Ray Bağlantı Sistemi” [Online]. Available: https://www.gurmakdemiryolu.com.tr/tr/urunlerimiz/w21-ray-baglanti-sistemi/. [Accessed July 7, 2020].
13. Indiamart, “Grooved rubber sole plates rail pad” [Online]. Available: https://www.indiamart.com/proddetail/grooved-rubber-sole-plates-rail-pad-20756032791.html. [Accessed July 7, 2020].
14. Kausel, E. 2010. Early history of soil–structure interaction. Soil Dynamics and Earthquake Engineering, 30(9), pp. 822–832.
15. Kerr, A. D., Cox, J. E., 1999. Analysis and Tests of Bonded Insulated Rail Joints Subjected to Vertical Wheel Loads. International Journal of Mechanical Sciences 41, p.1253-1272
16. Khajehdezfuly, A. 2019. Effect of rail pad stiffness on the wheel/rail force intensity in a railway slab track with short-wave irregularity. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. 233(10):1038-1049.
17. Koro, K., Abe, K., Ishida, M., Suzuki, T., 2004. Timoshenko beam finite element for vehicle-track vibration analysis and its application to jointed railway track. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 218(2):159-172
18. Lakusic, S., Ahac, M., Haladin, I., 2010. Experimental investigation of railway track with under sleeper pad. 10th Slovenian road and transportation congress, Ljubljana, Slovenia, 2010, pp. 20–22.
19. Loy, H., 2008. Under Sleeper Pads: Improving Track Quality while Reducing Operational Costs. European Railway Review, vol. 4, pp. 46–51.
20. Lundqvist, A., Dahlberg, T. 2005. Load impact on railway track due to unsupported sleepers. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 219(2), pp. 67–77.
21. Markine, V. L., Shevtsov, I., 2012. Experimental Analysis of the Dynamic Behaviour of Railway Turnouts, Civil-Comp Press, Proceedings of the Eleventh International Conference on Computational Structures Technology.
22. Michas, G., 2012. Slab track systems for high-speed railways. Master Degree Project, KTH Royal Institute of Technology, Stockholm.
23. Moderen, O., 2010. Balastsız demiryolu üstyapısının yapısal modellenmesi ve analizi. Doctoral dissertation, İTÜ Fen Bilimleri Enstitüsü.
24. Selig, E. T., and Li, Di., 1994. Track Modulus: Its Meaning and Factors Influencing It. Transportation Research Record 1470, TRB, National Research Council, Washington, D.C., pp. 47–54.
25. Selig, E. T., Waters, J. M., 1994. Track geotechnology and substructure management. London: Thomas Telford.
26. Skar, A., Klar, A., Levenberg, E. 2019. Load-Independent Characterization of Plate Foundation Support Using High-Resolution Distributed Fiber-Optic Sensing. Sensors, 19(16), 3518.
27. Song, X., Qian, Y., Wang, K., Liu, P., 2020. Effect of rail pad stiffness on vehicle–track dynamic interaction excited by rail corrugation in metro. Transportation Research Record, vol. 2674, no. 6, pp. 225–243.
28. Steffens, D., Murray, M. H., 2005. Establishing meaningful results from models of railway track dynamic behaviour. 8th International Heavy Haul Conference.
29. Suzuki, T., Iahida, M., Abe, K., Koro, K., 2005. Measurement on Dynamic Behaviour of Track near Rail Joints and Prediction of Track Settlement. QR of RTRI, Vol.46, No.2.
30. Terzaghi, K. 1955. Evaluation of Coefficients of Subgrade Reaction. Geotechnique, 5(4), 297-326.
31. Wehbi, Mohamed., Burrow, M., Shi, J., Ghatoara, G., 2013. Investigating the Effects of Soft Spots on the Functional and Structural Condition of a Railway Track. 4th Bear Post Graduate Conference in High Performance Computing, Birmingham, the UK.
32. Winkler, E. 1867. Die Lehre von der Elasticitat und Fastigkeit, Verlag von H. Dominicus, Prague.
33. Winkler, E. 1875. Der Eisenbahnoberbau, Verlag von H. Dominicus, Prague.
34. Witt, S., 2008. The Influence of Under-Sleeper Pads on Railway Track Dynamics. Report LiU-IEIA-08/00442-SE, Linköping University, Division of Solid Mechanics/IEI, Linköping, Sweden.
35. Xu, J., Wang, P., Ma, X., Gao, Y., Chen, R. 2016. Stiffness Characteristics of High-Speed Railway Turnout and the Effect on the Dynamic Train-Turnout Interaction. Shock and Vibration, pp. 1–14.
36. Yılmaz, A. 2015, Demiryolu Üstyapısında Balast Kirliliği. Mehmet Akif Ersoy Üniversitesi Fen Bilimleri Enstitüsü Dergisi, 6(1), 11-17.
37. Zhu, J. Y., 2005. On the effect of varying stiffness under the switch rail on the Wheel-rail dynamic characterictics of a high-speed turnout. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. 220(1): 69-75.
38. Zhu, K., Qian, Y., Edwards, J. R., Andrawes, B. O. 2017. Finite Element Analysis of Rail-End Bolt Hole and Fillet Stress on Bolted Rail Joints. Transportation Research Record: Journal of the Transportation Research Board, 2607(1), pp. 33–42.
39. Zimmermann, H. 1888, Die Berechnung des Eisenbahnoberbaues, Verlag W. Ernst and Sohn, Berlin.