考虑拱效应的复合地层盾构隧道开挖失稳分析

Soil Destabilization Analysis of Shield Tunnel Excavation Surface in Composite Strata Considering Arch Effect

根据盾构隧道开挖面的特点,考虑不同地层、不同隧道埋深条件下土体成拱效应,基于Paik圆弧拱理论建立失稳土体三维极限平衡理论分析模型。将经典三维楔形体模型改进为垂直面水平面均考虑拱效应的失稳土体三维模型,模拟盾构隧道开挖时前方土体的影响范围和影响大小,将上覆土压力计算方法扩展为三维形式,并采用土体条分法给出失稳土体极限平衡公式。最后利用MATLAB编程将模型计算结果与离心试验及其他理论模型进行了对比验证。结果表明:本文力学模型结果与离心试验结论更接近,可更准确地应用于开挖面最小支护压力参数的确定。

According to the characteristics of the excavation surface of shield tunnel,based on the analysis of the existing soil limit equilibrium theoretical model of shield tunnel excavation surface,considering the arch effect of soil body under different stratum and different tunnel burial depth conditions,a three-dimensional limit equilibrium theoretical analysis model of unstable soil body is established based on the Paik circular arch theory.Then the classical three-dimensional wedge-shaped body model is improved into a three-dimensional model of unstable soil body with arch effect in both vertical and horizontal planes.Finally,were compared with the centrifugal test and other theoretical models by using MATLAB programming to verify,and the results showed that the results of the mechanical model in this paper are closer to the conclusions of the centrifugal test and can be more accurately applied to the determination of the minimum support pressure parameters at the excavation surface.