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为研究排桩支护体系中的土拱效应的三维分布、体系的安全性及合理桩间距的计算方法,利用三维有限元程序PLAXIS 3D对排桩支护体系、施工开挖、堆载等过程进行模拟,分析了不同阶段土拱效应的分布情况及不同阶段的安全性。并根据土拱的三维分布特性改进了已有的桩间距计算方法。计算显示开挖过程中桩间土拱前塌落区与摩尔库伦塑性区基本重合,在基坑1/2~2/3深度处土拱效应最为明显、塌落区最大,建议用已有公式计算这一段对应的合理桩间距,用于工程设计。有限元计算显示,本文中建议的方法所计算的桩间距能保证支护的安全性符合要求。
In order to study the three-dimensional distribution of soil arching effect, the safety of the system and the calculation method of reasonable pile spacing in the piled piles support system, the three-dimensional finite element program PLAXIS 3D is applied to the piling support system, Simulation was carried out to analyze the distribution of soil arching effect in different stages and the safety in different stages. According to the three-dimensional distribution of soil arches, the existing calculation method of pile spacing is improved. The calculation shows that the soil collapse area before the soil arching in the process of excavation basically coincides with the Molucun plasticity area. The soil arching effect is most obvious at the depth of 1/2 ~ 2/3 of the foundation pit and the largest slump area. It is suggested that the existing formula Calculate the reasonable pile spacing corresponding to this section for engineering design. Finite element calculations show that the spacing of piles calculated by the proposed method in this paper can ensure the safety of the support meets the requirements.