框架板式无砟轨道梁端凸形挡台受力影响规律研究

Research on the law of the Influence of the Stress on the Convex Block at the Beam end of the Frame Slab Ballastless Track

为探明框架板式无砟轨道梁端凸形挡台受力的影响规律,结合现场对某线上框架板式无砟轨道监测结果,建立框架板式无砟轨道三维精细化静力分析模型,研究不同影响因素对梁端凸形挡台受力性能的影响规律。研究表明:梁端凸形挡台与底座板相连位置所受垂向拉应力较大,容易出现混凝土拉裂;凸形挡台受力随着梁端相对位移的增加整体呈非线性增加,当梁端相对位移超过80 mm时,凸形挡台的受力基本不再发生变化;扣件纵向阻力对凸形挡台的受力影响明显,当扣件纵向阻力超过7.5 kN/组时,凸形挡台底部可能会发生受拉破坏,现场应重点关注扣件的服役状态;建议当凸形挡台与轨道板相对位移超过5.3 mm时,应对梁端凸形挡台采取加固措施,防止凸形挡台拉裂;环形树脂的老化能一定程度劣化凸形挡台的受力。

In order to find out the influence law of the stress on the convex block at the beam end of the frame slab ballastless track,a three-dimensional refined static analysis model of the frame slab ballastless track is established,and the influence of different factors on the stress performance of the convex block at the beam end is studied based on field monitoring results of the frame slab ballastless track on a certain line.The research results show that the vertical tensile stress at the connection between the convex block at the beam end and the base plate is relatively large,which is likely to cause cracking of the concrete.The stress of the convex block increases nonlinearly with the increase of the relative displacement of the beam end.When the relative displacement of the beam end exceeds 80 mm,the stress of the convex block will not change any more.The longitudinal resistance of the fastener has obvious influence on the stress of the convex block;when the longitudinal resistance of the fastener exceeds 7.5 kN/group,the bottom of the convex block may be damaged by tension,and more attention shall be paid to the service status of fasteners on site.It is suggested that when the relative displacement between convex block and track plate exceeds 5.3 mm,corresponding reinforcement measures shall be taken for the convex block at beam end to prevent the convex block from cracking.The aging of circular resin can degrade the stress of the convex block to a certain extent.