桥墩温度梯度对桥上CRTS Ⅱ型板式无砟轨道纵向力的影响

针对桥墩温度梯度引起的桥上CRTSⅡ型板式无砟轨道纵向附加力与变形, 以梁-板-轨相互作用原理和有限元法为基础, 建立了多跨简支梁桥和大跨连续梁桥上CRTSⅡ型板式无砟轨道无缝线路空间耦合模型, 详细考虑了钢轨、轨道板、CA砂浆、底座板及桥梁等主要结构和细部结构的空间尺寸与力学属性; 采用单位荷载法计算了桥墩纵向温差作用引起的墩顶纵向位移, 分析了墩顶位移影响下桥上无砟轨道无缝线路纵向力与位移的分布规律。分析结果表明: 当各墩顶发生均匀位移时, 多跨简支梁桥和大跨连续梁桥上无砟轨道无缝线路纵向力分布规律及其最大值一致, 且随着墩顶均匀位移的增加而线性增大, 轨板相对位移峰值均出现在两侧桥台、台后锚固结构末端以及第2跨和最后一跨固定支座墩顶处; 当墩顶均匀位移为5 mm时, 多跨简支梁桥和大跨连续梁桥上钢轨最大纵向力分别为79.62和79.54 kN, 最大纵向位移分别为4.94和4.91 mm, 轨板最大相对位移均为0.23 mm; 当各墩顶发生不均匀位移时, 钢轨纵向力及轨板相对位移均在邻墩位移存在差异处发生突变, 多跨简支梁桥上固结机构纵向受力大于大跨连续梁桥; 对于高墩桥梁, 需重点关注相邻墩身高差最大处的轨板相对位移、底座板与桥梁相对位移及固结机构的纵向受力。 

Effect of pier temperature gradient on longitudinal force of CRTSⅡslab ballastless track on bridge

For the longitudinal additional force and deformation of China railway track system(CRTS) Ⅱ slab ballastaless track on bridge caused by the pier temperature gradient, the spatial coupling models of CRTS Ⅱ slab ballastless track continuous welded rails(CWR) on the multi-span simply supported beam bridge and long-span continuous beam bridge were established by using the finite element method based on the beam-slab-rail interacting principle. Both the dimensions and mechanical properties of main and detail structures, such as rail, track slab, cement asphalt(CA) mortar, base plate and bridge, were considered in detail. The longitudinal displacement of pier top caused by the action of longitudinal temperature difference of pier was calculated by the unit load method, to analyze the distribution rules of longitudinal force and displacement of ballastless CWR on the bridge under the influence of displacement of pier top. Analysis result shows that when the uniform displacement of each pier top occurs, the distribution laws and the maximum values of longitudinal force of ballastless track CWR on the multi-span simply supported beam bridge and long-span continuous beam bridge are basically the same, and increase linearly with the increase of uniform displacement of pier top. The peak relative displacement between the rail and track slab appears at the ends of abutment on both sides, the anchorage structures behind the abutments, tops of the second and last spans fixed support piers. When the uniform displacement of pier top is 5 mm, the maximum longitudinal forces of rails on the multi-span simply supported beam bridge and long-span continuous beam bridge are 79.62 and 79.54 kN, respectively, the maximum longitudinal displacements are 4.94 and 4.91 mm, respectively, and the maximum relative displacement between the rail and track slab is 0.23 mm. When the uneven displacement occurs at the top of each pier, the longitudinal force of rail and the relative displacement between the rail and track slab change abruptly at the displacement difference between adjacent piers. The longitudinal force of consolidation mechanism on the multi-span simply supported beam bridge is greater than that of long-span continuous beam bridge. For high pier bridges, it is necessary to pay more attention to the relative displacement between the rail and track slab at the maximum height difference between adjacent piers, the relative displacement between the base plate and bridge and the longitudinal force of consolidation mechanism.