宽窄接缝与CA砂浆耦合伤损对无砟轨道-简支梁桥结构受力性能影响

Influence of coupled damage of wide-narrow juncture and CA mortar on mechanical performance of ballastless track-simply supported bridge structure

基于弹性地基梁体理论,考虑宽窄接缝与轨道板之间界面开裂与CA砂浆脱空耦合伤损,建立伤损状态下的CRTS Ⅱ型板式无砟轨道-简支梁桥结构有限元模型,分析宽窄接缝与CA砂浆不同伤损型式和不同位置耦合伤损尺寸在正温度梯度荷载作用下对无砟轨道-简支梁桥结构受力及变形的影响。研究结果表明:宽窄接缝与CA砂浆耦合伤损较宽窄接缝界面开裂或CA砂浆脱空单一伤损型式对结构受力与变形更为不利;当耦合伤损面积超过0.975 m×0.765 m,长度超过0.975 m或宽度超过0.51m时,轨道板拉应力超过其抗拉强度,影响结构的正常使用;随耦合伤损尺寸的增加,轨道板和CA砂浆的垂向位移均显著增大,底座板和桥梁的垂向位移呈微弱减小趋势;宽窄接缝与CA砂浆耦合伤损位于轨道板板边对结构受力和变形影响最大,耦合伤损位于板端次之,耦合伤损位于板角影响最小。

Based on elastic foundation beam theory, considering the cracking of the interface between wide-narrow juncture and track slab coupled with CA mortar void, finite element model of CRTS Ⅱ ballastless track-simple supported bridge structure under damage condition was established. Through this model, the influence of different coupled damage types and different coupled damage size at different positions on the stress and deformation of the structure under positive temperature gradient load were studied. The results show that coupled damage is more unfavorable than wide-narrow juncture crack or CA mortar void single damage type of the structural;when the coupled damage area exceed 0.975 m×0.765 m, the length exceeded 0.975 m, or the width exceeded 0.51 m, the tensile stress of the track slab exceed its tensile strength, affecting the normal use of the structure;with the increase of the coupled damage size, vertical displacements of the track slab and the CA mortar increase significantly, and vertical displacements of the base slab and the bridge decrease slightly;coupled damage which at the edge of the slab had great influence, which at the ends of the slab played the second role, and which at the corner of the slab had the least impact.