CRTS Ⅱ型板断裂条件下桥上无缝线路伸缩力特性

为了研究桥上CRTSⅡ型轨道板断裂条件下轨道、桥梁结构纵向受力变形规律及其影响，基于有限元法和梁-板-轨相互作用机理，建立桥上CRTSⅡ型板式无砟轨道无缝线路空间耦合模型，分析不同轨道板断缝位置、断缝宽度、裂缝深度及轨道板、底座板伸缩刚度对断板条件下桥上无砟轨道无缝线路伸缩力分布规律的影响. 研究结果表明:在计算轨道板断裂条件下桥上无砟轨道无缝线路伸缩力时，应根据不同检算部件选取最不利的断板位置，建议将轨道板断缝宽度和深度分别取2 mm和200 mm、轨道板、底座板伸缩刚度折减至10%～50%，计算结果是偏安全的且不失一般性；轨道板断裂增加了断缝处CA （cement asphalt）砂浆层及底座板断裂的风险，断板侧的钢轨纵向位移及轨板相对位移均在断缝处急剧变化. 

Expansion-Constriction Force Characteristics of Continuously Rails on Bridge under Fracture Condition of CRTS Ⅱ Track Slab Welded

In order to study the longitudinal stress and deformation characteristics and their influences on track and bridge structure under the fracture condition of CRTSⅡ track slab, a spatial coupling model based on the finite element method and bridge-slab-rail interaction mechanism was established. This model can analyze the influences of crack location, width and depth of track slabs, as well as the expansion-constriction stiffness of track slab and bed plate, on distribution rules of the expansion-constriction force of continuously welded rail (CWR) on bridge. Results show that, in order to calculate the expansion-constriction force of CWR on bridge under the fracture condition of CRTSⅡ track slab, a most unfavorable fracture location at track slab should be selected according to the different checking parts. Meanwhile, the crack width and depth of track slab are suggested to be 2 mm and 200 mm, respectively, and the expansion-constriction stiffness of track slab and bed plate should be reduced to 10%?50%, since in this way the calculation result is conservative without losing generality. Track slab fracture increases the fracture risk of cement asphalt mortar screed and bed plate; the longitudinal displacement of rail and the relative displacement between rail and track slab on the side of broken slab are changed dramatically at the crack.