新建河道下穿既有高铁桥梁安全分析

针对新建河道下穿既有高铁桥梁施工过程(排桩支护结构施工、U型槽河道施工、河道最高设计水位)对桥墩以及桩基础的影响进行数值分析。结果表明,河道下穿施工引起的既有高铁桥梁桥墩的变形量在0.5 mm以内,满足《高速铁路设计规范》中限值要求,说明新建河道对高铁桥梁影响较小。河道下穿施工过程中,在距离桩顶(0.28~0.34)倍桩长处的轴力出现最大值。排桩支护结构施工时,桩侧摩阻力随桩基深度的增加先减小后基本不变;U型槽河道施工及最高设计水位时,桩侧摩阻力随桩基深度的增加先增大后基本稳定。

A numerical analysis is carried out on the influence of the construction process of the newly-built river crossing the existing high-speed railway bridge(row pile supporting structure construction,U-shaped channel construction and the highest design water level of the river)on the pier and pile foundation.The results show that the deformation of the pier of the existing high-speed railway bridge caused by the river underpass construction is less than 0.5 mm,which meets the limit requirements of the"Code for High-speed Railway Design",indicating that the new river has little influence on the high-speed railway bridge.In the process of river penetration construction,the maximum axial force appears at the distance from the top of the pile(0.28~0.34)times the length of the pile.During the construction of the row pile supporting structure,the pile lateral friction resistance decreases at first and then remains basically unchanged with the increase of the pile foundation depth;in the U-shaped channel construction and the highest design water level,the pile lateral friction resistance increases at first and then basically stable with the increase of the pile foundation depth.