地铁沉降地段易修复板式无砟轨道限位方案研究

为研究易修复板式无砟轨道在地铁中应用的可行性,通过建立2种限位方案的非线性有限元模型,分析该结构在直、曲线段的承载能力,并在此基础上考虑大沉降地段填充后对轨道结构安全性的影响。研究表明:(1)"中心排水沟+顶升预埋件"的易修复板式无砟轨道能更好地应用于富水软土沉降地段的运营环境,并便于后期维护施工;(2)正常情况下2种结构设计方案均能满足强度设计要求,但发生沉降填充修复后,限位结构受力受横向荷载影响较大,其安全性检算是该类轨道设计的关键;在相同大沉降填充条件下,从限位结构受力方面来看,板下4凸台方案明显优于2凸台方案;(3)在进行地铁易修复板式无砟轨道结构设计时,应保证在最不利荷载工况下单块轨道板范围内限位结构受力对称均匀,并考虑长期使用条件下轨道板的横向稳定性,推荐采用板下4凸台方案。

Research on the Position-limitation of Easily Repaired Ballastless Slab Track in the Subsidence Area of Subway

In order to study the feasibility of easily repaired ballastless slab track in subway,the bearing capacities of the structures in straight and curved sections are analyzed based on two kinds of nonlinear finite element models of position-limitation program.On this basis,the influence of large subsidence area filling on the safety of the track structure is studied.The results show that:(1)The easily repaired ballastless slab track of"central drainage ditch and jacking embedded parts"can be better applied to the operating environment of the water-rich and soft soil subsidence area and facilitate post-maintenance construction.(2)Under normal circumstances,the two structural design programs can meet the strength design requirements,but after the subsidence and filling recovery,the force of position-limitation structure is greatly affected by lateral load,and the safety checking of position-limitation structure is the key to the design of repairable track.Under the same large subsidence filling conditions,the program of 4 convex platform under the slab is obviously superior to that of 2 convex platform in view of the force on the position-limitation structure.(3)In the design of the easily repaired ballastless slab track structure of the subway,it should be ensured that the stress of position-limitation structure within the scope of the single track slab is symmetrically uniform under the most unfavorable load conditions.Considering the lateral stability of the track slab under long-term operation,it is recommended that the program of 4 convex platform under slab should be adopted.