欠固结地基边坡与桩基相互作用分析

Analysis of interaction between slope and pile foundation on underconsolidated soil

当边坡地基土处欠固结时,不仅要考虑边坡区桩基负摩阻力的影响,而且应考虑边坡土体对桩基的侧向挤压。但是目前主要规范和手册对后者并无具体规定。针对该问题,结合接岸工程设计,基于PLAXIS岩土工程有限元数值模拟软件,采用软土模型和摩尔-库仑模型对欠固结地基边坡土体与近岸桩基相互作用进行分析。结果表明:边坡稳定计算在不考虑桩基作用的情况下偏于安全,但是桩基设计不考虑边坡土体固结变形的影响是不安全的。建议桩基设计应考虑边坡土体侧向土压力对桩的作用,特别是欠固结地基边坡与桩基相互作用其受力特点复杂,边坡土体后期固结变形对桩基影响更加明显,设计时应引起重视。

When the slope foundation soil is underconsolidated,not only the influence of the negative skin friction of the pile foundation in the slope area,but also the lateral extrusion on the pile foundation due to slope soil should be considered.But no specific provisions for the latter issue are recommended in the current code and manuals.To solve this problem, combining the actual engineering design, we analyze the interaction of the underconsolidated soil foundation slope and pile foundation by using the soft soil model and the Mohr-Coulomb model based on geotechnical engineering finite element simulation software PLAXIS.The result shows that the calculation of slope stability tends to be safe without considering the effect of pile foundation;however the calculation of pile foundation tends to be unsafe without considering the influence of the soil consolidation deformation of the slope.It is suggested that the design of pile foundation should consider the effect of lateral soil pressure on the pile due to the slope deformation,especially when the interaction between the under-consolidated foundation slope and the pile foundation is complex,more attention should be paid to the pile design,for the consolidation settlement of slope soil has obvious influence on pile foundation.