采用小应变硬化土(HSS)土体本构模型,建立同步开挖间距为1~8倍基坑开挖深度的相邻基坑有限元模型.考虑固渗耦合,分析不同基坑间距对坑间土堤沉降、支护桩弯矩和位移的影响.分析结果表明:相邻基坑间距小于等于4倍基坑开挖深度时,相互影响较强,需考虑相邻基坑施工引起的共同沉降,可采用有限土压力理论来对支护结构进行受力变形分析,减小桩径和配筋;间距大于4倍基坑开挖深度时,相互影响较弱,坑间土堤变形接近独立基坑,对支护结构的内力及变形影响也较小.
Hardening soil model with small strain stiffness (HSS) soil constitutive model was used to establish the finite element model for synchronously excavated adjacent foundation pits spacing 1 to 8 times of the excavation depth of foundation pits. Considering the solid-infiltration coupling, the influence of spacing on the settlement curve of embankment between adjacent foundation pits, the bending moment and the displacement of the supporting piles were analyzed. The analysis results show that: when the spacing is less than or equal to 4 times of the excavation depth of foundation pits, the interaction is strong, the settlement caused by the construction of adjacent foundation pits should be considered, the force and deformation of the supporting structure would be analyzed by the finite earth pressure theory, the size of pile and re- inforcement ratio would be reduced. When the spacing is greater than 4 times of the excavation depth of foundation pits, the interaction is weak. The deformation of the embankment between adjacent foundation pits is similar to independent pit. The impact to the deformation and stress is also weak.