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基坑开挖具有明显的空间效应,开挖尺寸的变化会引起空间性状的改变,进而影响深基坑的稳定性。本文通过建立摩尔-库伦屈服准则的三维基坑阶梯开挖模型,分析了郑州地铁一号线桐柏路站不同施工工况下的基坑变形,将计算值与实测值作对比,结果较为接近。为了更直观地分析基坑空间效应对围护结构变形的影响,在其他施工参数设置不变的情况下,通过增大第一、二层钢支撑处的开挖深度建立了基坑超挖模型,分析了尺寸效应的改变对围护桩变形的影响程度。结果表明:控制基坑开挖临界面尺寸可有效地减小围护结构的变形,既保证了基坑施工过程的安全稳定,又提高了施工效率。
The excavation of foundation pit has obvious space effect, and the change of excavation size will cause the change of spatial characters, which will affect the stability of deep foundation pit. Based on the three-dimensional excavation ladder excavation model with Mohr-Coulomb yield criterion, the deformation of foundation pit under different construction conditions of Tongbai Road Station of Zhengzhou Subway is analyzed in this paper. Comparing the calculated value with the measured value, the result is close . In order to more intuitively analyze the effect of the space effect of the foundation pit on the deformation of the retaining structure, an excavation over excavation model was established by increasing the excavation depth of the support of the first and second floors under the condition of other construction parameters being set , The effect of the change of size effect on the deformation of the retaining pile is analyzed. The results show that controlling the size of the excavation dredging surface can effectively reduce the deformation of the retaining structure, which not only ensures the safety and stability of the excavation but also improves the construction efficiency.