基于改进应变楔模型的固体–散体串联组合桩鼓胀变形及沉降分析

Lateral bulgings and settlements of solid-bulk tandem compound piles based on modified strain wedge model

针对传统碎石桩易在桩顶1~3倍桩径的深度范围内发生鼓胀破坏的现象,首先,在现有工艺的基础上提出一种固体(混凝土)–散体(碎石散体材料)串联组合桩,并简要阐述其承载特性、施工工艺及破坏模式;其次,建立了串联组合桩鼓胀变形的计算模型,探讨串联组合桩的鼓胀变形机理;然后,对应变楔模型进行修正,并结合广义胡克定律,计算固体–散体串联组合桩的鼓胀变形值及桩身沉降值;最后,通过传统碎石桩及筋箍碎石桩鼓胀变形及沉降试验验证所提理论方法的合理性,结果表明:理论计算值与试验结果吻合较好,可为碎石桩复合地基设计提供一定的参考,具有理论及工程应用价值。

This paper is presented to respond to the phenomenon that swelling and failure are liable to appear within the top of the traditional gravel piles(within depth range of 1 to 3 times the pile diameter). Firstly, the solid(concrete)-bulk(gravel bulk material) tandem composite pile is proposed on the basis of the existing procedures, and the bearing mechanism, construction technology and failure mode of the tandem composite piles are introduced briefly. Secondly, a model for the bulging deformation of tandem composite piles is established to study the mechanism of the bulging deformation of tandem composite piles. Then, based on the modified strain wedge model and the generalized Hooke’s law, the bulging deformations and settlements of the solid-bulk tandem composite piles are predicted. Finally, the proposed method is verified by the tests on the swelling deformations and settlements of the traditional gravel piles and reinforced-hoop-gravel piles. The comparative results show that the predicted values are in good agreement with the experimental ones, which indicates that the reference is thus provided, which is of theoretical and engineering application values for the design of the composite foundation of gravel piles.