钢管-水泥土组合桩的抗拔性能

针对传统抗拔桩承载能力的局限性,根据劲性搅拌桩施工及荷载传递特点,提出钢管-水泥土组合抗拔桩形式,并借助ANSYS数值模拟软件,分析钢管直径及壁厚对组合桩承载能力及破坏模式的影响。结果表明:钢管直径对组合桩的抗拔性能影响显著。钢管直径小于0.4 m时组合桩的承载力增幅很大,达到0.4 m时承载力接近极限值;钢管直径为0.3~0.4 m时组合桩破坏模式较合理。钢管壁厚对组合桩的抗拔性能影响较小。壁厚为10 mm时组合桩的极限承载力增幅较大,钢管壁厚宜取10 mm。钢管壁厚不影响组合桩的破坏模式,破坏均发生在钢管与外桩界面。该研究为改善水泥土搅拌桩的抗拔性能提供了参考。

Effect of steel pipe on withdrawal resistance capacity of steel-cement composite pile

Aimed at addressing the limited bearing capacity inherent in conventional uplift piles, this paper proposes a steel-cement composite pile, a new combination building on the behavior of struc- ture and load transfer in reinforced mixing piles. The paper goes further into an analysis of the effects of steel pipe diameter and thickness on the composite pile bearing capacity and failure modes, using nu- merical simulation software ANSYS. The analysis finds that steel pipe diameter exerts a significant effect on the withdrawal resistance behavior of composite piles, as is demonstrated when a steel pipe with a di- ameter of less than 0.4 m, provides a significant increase in bearing capacity of composite piles ; a steel pipe with a diameter of up to 0.4 m gives composite piles the bearing capacity close to the limit; and a steel pipe with a diameter ranging from 0.3 to 0.4 m affords a more reasonable failure mode. Pipe wall thickness has a less effect on withdrawal resistance performance, as is evidenced by the fact that a 10 mm-thick pipe wall provides a greater increase in the uhimate bearing capacity, suggesting that a pipe wall thickness is set to be 10 mm. Pipe wall thickness produces no effect on the failure mode, due to the damage occurring only in the interface between steel pipe and the outer pile. This paper may serve as a reference for improving the performance of reinforced composite pile.