Study on the effect of CRTS I ballastless track caused by angular settlement in
transition section between bridge and subgrade
LOU Ping HUANG Ganggui
School of Civil Engineering, Central South University Key Laboratory of Heavy Railway
Engineering Structure of Education Ministry, Central South University
Because the supporting stiffnesses of the bridge and subgrade are different and the subgrade behind the abutment is difficult to fill and compact, the high speed railway bridge-subgrade transition section is easy to produce the angular settlement, which leads to diseases such as interlayer separation, structural crack and subgrade void in the ballastless track, affecting the operation comfort and safety of high-speed train. This paper takes CRTS III slab ballastless track in the high speed railway bridge-subgrade transition section as the research object, establishes the ballastless track spatial coupling model in the transition section by using ABAQUS finite element software, and studies the influence laws of the angle of settlement in the transition section and the thickness of base on the interlayer separation of ballastless track. In addition, the plastic damage characteristics of concrete isconsidered, and then the influence of different load combinations and base thickness on the stress and deformation of track are analyzed. The results show that the angle of settlement has a great influence on the stress and deformation of track. When the angle increases from 0.5‰ to 1‰, the length of separation between the self-compacting concrete layer and the base increases from 0 to 1.46 m, and the amplitude of separation increases from 0.99 mm to 3.13 mm. The length of subgrade void increases from 0 to 0.92m, and the amplitude of subgrade void increases from 0.51 mm to 2.53 mm. At the lower end of angular settlement, compared with subgrade void, the distribution range of separation joints between self compacting concrete layers is larger, but the amplitude is smaller; At the upper end of corner settlement, the distribution range and amplitude of interlayer separation joints are larger than that of subgrade void. The increase of the thickness of the base can reduce the separation between the track layers and the structural cracks caused by the angular settlement, and the range of damage and the maximum value of damage factor are reduced. It is suggested to increase the thickness of the base to 50 cm, which can effectively improve the adverse influence of the allowable angular settlement with 1‰ in the transition section specified in the code on the service state of the CRTS Ⅲ ballastless track.
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