覆土波纹钢板拱桥施工过程的受力分析

Mechanical Analysis of Buried Corrugated Steel Arch Bridge during Construction

基于一座实际的覆土波纹钢板拱桥,利用有限元方法建立了三维空间受力分析模型,采用现行公路规范的方法计算了不同覆土施工阶段的土压力荷载,对该桥覆土的施工过程进行了模拟,计算分析了覆土回填过程中关键截面变形和内力的变化规律。计算和分析结果表明,波纹钢板拱桥的各关键截面变形和内力随覆土回填过程发生较大变化,覆土初期拱两侧受到填土压力的挤压而下挠,同时拱顶处出现了反拱现象,且随覆土高度的增加拱顶处反拱逐渐增大,各截面的应力也均逐渐增大;覆土回填至拱顶之后,随覆土高度的增加拱顶处的反拱逐渐减小,同时拱顶拉应力也明显减小,整个拱圈趋于受压状态。因此,施工中应严格分层对称回填、压实,并应特别注意覆土回填至拱顶附近时结构的位移和应力变化。

Based on a real buried corrugated steel arch bridge, a 3D finite element model for mechanical analysis was established.The earth pressures during various backfilling stages was calcutated and the process of the backfilling construction was simulated according to the current highway specification. The variation rifles of stresses and deformations of the key sections of the arch ring during backfilling were calculated and analysed. The result shows that （1） The stresses and deformations of the key sections vary significantly during backfilling process. The haunch of the arch appears deflection and the crown of the arch appears invert during the initial backfilling stage due to the compression of the backfilled soil from the both sides. The invert of the vault increases until the backfill approaches to the vault. The stresses of all the key sections increase gradually. （2） The invert of the vault decreases when the backfilling surpass the vault and the tensile stress of the vault also decreases and the whole arch ring tends to be compressed. So the layered and symmetrical compaction must be controlled strictly during the backfilling process and the stress and deformation of the corrugated steel arch must be paid more attention when the backfilling process is closed to the crown of the arch.