Poliüretan ile Güçlendirilmiş Balastın Hareket Eden Tekerlek Yükü Altındaki Deformasyon Davranışının Nümerik Olarak İncelenmesi

Öz

Hareket eden tekerlek yükünden dolayı balastlı demiryolu hatlarında meydana gelen düşey deformasyonlar özellikle yüksek tren hızlarında ve zayıf taban zemini koşullarında hat düzensizliklerine sebep olmaktadır. Bu durum ise hat güvenliğini ve inşaat sonrası maliyeti olumsuz etkilemektedir. Bu çalışmada farklı miktarlarda poliüretan ile güçlendirilmiş balast tabakasının (70 kg/m3, 140 kg/m3 ve 210 kg/m3), zayıf taban zemini koşulunda ve farklı tren hızlarındaki (100 km/h, 200 km/h ve 300 km/h) düşey deformasyon davranışları sayısal olarak incelenmiştir. Bu kapsamda geliştirilen iki boyutlu nümerik modellerde statik ve hareket eden tekerlek yükleri uygulanmıştır. Analiz sonuçlarına göre poliüretan kullanımı, zayıf zemine oturan balastlı demiryolu hattında meydana gelen düşey deformasyonu önemli oranda iyileştirmektedir (>%87). Öte yandan düşük hızlarda düşük poliüretan miktarları kullanılabilirken, balast agregaları arasında oluşan daha güçlü poliüretan yapıdan dolayı artan tren hızlarında yüksek poliüretan miktarları tercih edilmelidir. Ayrıca poliüretan ile güçlendirilmiş veya güçlendirilmemiş bir demiryolu hattının analizinde statik tekerlek yükünün yerine hareket eden tekerlek yükü kullanılmalıdır.

Anahtar Kelimeler

• Poliüretan
• Balast
• Hareket eden tekerlek yükü
• PLAXIS
• Balastlı demiryolu hattı

Numerical Investigation of Deformation Behavior of Ballast Reinforced with Polyurethane Under a Moving Wheel Load

Öz

The vertical deformation in ballasted railway tracks due to moving wheel loads causes track irregularities, particularly at high train speeds and under poor subgrade conditions. This adversely affects track safety and post-construction cost. In this study, the vertical deformation behavior of ballast reinforced with polyurethane in different amounts (70 kg/m3, 140 kg/m3 ve 210 kg/m3) under poor subgrade condition and at different train speeds (100 km/h, 200 km/h, and 300 km/h) was numerically investigated. In this context, static and moving wheel loads were applied in the developed two-dimensional numerical models. According to the results, the use of polyurethane significantly improves the vertical deformation in the ballasted railway track resting on poor subgrade soil (>87%). On the other hand, while low amounts of polyurethane can be used in tracks with low train speeds, high amounts of polyurethane should be preferred in tracks with high train speeds due to stronger polyurethane bonding between ballast particles. Moreover, instead of static wheel load, a moving wheel load should be taken into consideration in the analysis of a railway track with and without polyurethane.

Anahtar Kelimeler

• Polyurethane
• Ballast
• Moving wheel load
• PLAXIS
• Ballasted railway track

Kaynakça

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