سيدحسين طبسي

The lateral resistance of railway tracks is a key factor in maintaining geometric stability an‎d operational safety, particularly in high-speed an‎d heavily trafficked lines. Transition zones, due to the abrupt change in track stiffness an‎d structural conditions, are considered critical points where reduced lateral resistance can lead to premature failure an‎d increased maintenance costs. The main objective of this study is to investigate, both experimentally an‎d numerically, the lateral resistance performance of ballasted railway tracks in transition zones an‎d to eva‎luate strengthening strategies for its improvement. To this end, field tests of lateral resistance were conducted using the panel displacement method at the tunnel entrance of Tehran railway station. Three different track configurations were assessed: (i) conventional ballasted track, (ii) ballasted track with an approach concrete slab, an‎d (iii) ballasted track with an approach slab combined with an additional rail. The results showed that the lateral resistance of the ballasted track was 19.37 kN, which increased to 20.75 kN with the use of the approach slab (an improvement of 7.1%). In the case of the ballasted track with both the approach slab an‎d the additional rail, the lateral resistance reached 28.51 kN, representing a significant enhancement of 47.2% compared to the initial condition. To better understan‎d track behavior an‎d validate the field findings, a three-dimensional finite element model was developed in ABAQUS. The numerical results showed good agreement with the field data an‎d enabled a parametric investigation of influencing factors. A sensitivity analysis was conducted on three key parameters: ballast elastic modulus, density, an‎d internal friction angle. The findings indicated that increasing the ballast elastic modulus had the greatest impact, improving lateral resistance by up to 41.6%, while the friction angle an‎d ballast density also played important roles. Overall, this study highlights the effectiveness of reinforcement strategies such as the use of approach slabs an‎d additional rails in enhancing the lateral stability of transition zones, while also emphasizing the critical role of ballast mechanical properties as a complementary factor in improving railway track lateral resistance.

مقاومت جانبي خط آهن بالاستي , ناحيه انتقال , ريل اضافي , دال بتني ورودي , تست جابه‌جايي پانل خط , تست ميداني

Lateral Resistance of Ballasted Track , Transition Zone , Additional Rail , Approach Slab , LTPT , Field Test

Seyed Hossein Tabasi

Dr. Zakeri Dr. Mosayebi