轨道板损伤对桥上CRTSⅡ型板式无砟轨道力学特性的影响
Influence of slab damage on mechanics characteristic of CRTSⅡ slab track on bridge

基于轨道板与底座板分离，建立了考虑轨道板损伤的CTRSⅡ型板式无砟轨道与桥梁相互作用力学模型，并采用有限单元法求解，分析了轨道板全断面开裂和更换轨道板对大跨度连续梁桥上钢轨、底座板、剪力齿槽、桥梁墩台及砂浆受力的影响. 结果表明： 轨道板全断面开裂后钢轨、底座板的纵向力增加，最大增幅分别为22.55和131.48 kN，轨道板纵向力则降低，剪力齿槽、桥梁墩台的纵向力变化很小；轨道板全断面开裂对钢轨和底座板纵向受力影响范围分别为32～50 m和24～36 m；桥梁伸缩或列车制动作用下全断面开裂位置的砂浆阻力接近其极限阻力，为避免砂浆开裂应及时更换轨道板；更换轨道板对底座板纵向受力影响最大，建议轨道板进行更换作业的板温变化幅度控制在15 ℃以内．
Based on separation of slab from longitudinal continuous base layer (LCBL)，a mechanics model of interaction between CRTSⅡ slab track and bridge was established by considering damage of slab. Finite element method was used for solution of the mechanics model. On a long span continuous beam bridge，influence of slab all-section crack and its replacement on rail，foundation plate，shear groove，and bridge pier were analyzed. The results show that longitudinal forces of rail and foundation plate are increased when slab is cracked，the largest increase of rail longitudinal force is 22.55 kN，the largest increase of LCBL longitudinal force is 131.48 kN. Longitudinal force of slab is decreased sharply when slab is cracked，but longitudinal forces of shear groove and bridge pier change little. Influence lengths of slab crack on rail longitudinal force is 32~50 m，and on longitudinal force of foundation plate is 24~36 m. With action of bridge expansion or train brake，mortar resistance is close to its limitation at location where slab cracked，so slab must be replaced timely to prevent mortar from crack. Influence of slab replacement on force of foundation plate is the greatest. It is recommended that temperature change of slab between replacement and laying is less than 15 ℃