施工顺序对大跨钢结构桩基位移影响分析

Analysis on influence of construction sequence on displacement of pile foundation for large-span steel structure

受回填土等不平衡堆载作用的被动桩桩身在附加作用下易发生位移,对结构安全将产生不利影响。基于某大跨斜撑钢结构遗址建筑施工过程,采用MIDAS/Gen建立精细化有限元模型,采用m法分析施工过程中承台周围回填土抗力及预应力张拉对桩顶位移及承台扭转的影响,并与实测数据进行对比。分析结果表明:随上部结构施工的进行,在施加预应力和考虑回填土作用的条件下,结构的水平位移控制效果显著;早期进行周围回填土回填,承台水平扭转值小,对结构的影响小。

Passive piles subjected to unbalanced load such as backfill soil are prone to displacement under additional action, which will have adverse effects on structural safety. Based on construction process of a large-span slanted braced steel structure site building, MIDAS/Gen was used to establish a fine finite element model, and m method was used to analyze the influence of backfill soil resistance around the cap and prestress tension on displacement of pile top and torsion of the cap during the construction process, and the results were compared with the measured data. The analysis results show that with the construction of the superstructure, the horizontal displacement control effect of the structure is significant under the conditions of applying prestress and considering backfill soil action. When the surrounding backfill soil is backfilled in the early stage, the horizontal torsion value of the cap is small and the influence on the structure is small.