Adaptability of Prefabricated Track Slab Dimensions to Track Alignments in Urban Rail Transit

Abstract

Objective By investigating the adaptability relationship between prefabricated track slab dimensions and track alignments, and proposing reasonable prefabricated slab dimensions based on corresponding constraints, a basis for the engineering design and standardization of prefabricated track slabs is provided. Method Prefabricated track slabs can achieve planar curve alignment through substituting straight segments for curved segments and adjusting fasteners laterally. Construction of transition curve and vertical curve alignment is achieved through adjusting fasteners vertically. The expressions of the allowable lateral and vertical adjustment amounts of the fasteners in relation to slab length are derived based on geometric relationships. Through geometric relationships, the expression of the relationship between prefabricated slab length and width is determined based on the allowable value of slab gaps. Result & Conclusion Research shows that the track slab length limit is closely related to the allowable lateral and vertical adjustment amounts of the fasteners, while the alignment is not a limiting factor for prefabricated slab width. It is recommended to set the allowable lateral adjustment of fasteners to 2 mm, and the allowable vertical adjustment to 15 mm. For the same line, it is suggested that the specifications of prefabricated slab lengths should not exceed two types. When track curve radius is R ≥ 950 m, slabs with a length of 5.9 m are recommended. For curve radii 300 m ≤ R < 950 m, slabs with a length of 3.5 m are recommended. When R<300 m, fasteners with large lateral adjustment amount are recommended.

Keywords

• urban rail transit
• prefabricated track slab
• track alignment
• dimension specification