EFFECT OF LAND SUBSIDENCE ON REGULARITY OF DOUBLE-BLOCK BALLASTLESS TRACK

A ballastless track is particularly sensitive to the deformation and settlement of its foundation soil. If the deformation of the foundation soil is too large, the stress and life of the ballastless track will be affected significantly. Moreover, the comfort and running stability of high-speed trains will be suffered. In this paper, for the double-block ballastless track on a roadbed, a beam-plate-solid spatial coupling model was established based on the finite element method. The research was conducted on the relationship between the regularity of a double-block track system and the amplitude, the scope and type of the ground uneven settlement. The results showed that the settlements of a ballastless track and its subgrade layers approximately showed a linear relationship with the increase of land subsidence. The settlement difference between the support layer and the surface layer of a subgrade was large enough to cause gaps between the two layers. The gap between a track and its subgrade was obvious when the land subsidence amplitude was 20mm with a wavelength of 15m. When the subsidence range was beyond 15m, the deformation curves of structures became flat and the curvature radius of a rail surface became larger with the increase of land subsidence. Faulting and angular-type uneven settlements were more easily to cause a settlement difference, the gaps between a track structure and its subgrade, and even cracking at the knuckle point. The magnitude of the angle of an angular-type settlement directly affected the regularity of a rail surface.