软土狭长深基坑施工三维精细化模拟及二维等效分析方法

3D Refined Simulation and 2D Equivalent Analysis Method for Construction of Narrow and Deep Foundation Pits in Soft Soil

针对上海软土地区典型狭长深基坑建立三维精细化模型计算分析,采用修正剑桥本构并考虑结构-地层相互作用,分析结果表明,精细化数值模拟可以较好地反映基坑工程的力学性态;通过建立相应的二维等效分析方法,并结合三维精细化模拟得出的狭长基坑空间效应PSR分布规律,通过二维等效分析即可推断整个三维模型的分析结果,从而大幅提高分析效率。新方法解决了传统有限元分析时,过于简化的模拟无法反映基坑复杂特性,过于精细化的模拟则建模代价过高、分析效率较低,难以满足设计方案变更、施工风险预测的时效性要求的问题,为有限元分析提供了一种新的思路。

A 3D refined model is established for the calculation and analysis of typical narrow and long deep foundation pits in the soft soil area of Shanghai.The modified Cambridge constitutive model is adopted,and the structure-stratigraphic interactionis considered.The analysis results show that the refined numerical simulation can better reflect the mechanical properties of foundation pit engineering;by establishing a corresponding 2D equivalent analysis method and combining it with the spatial effect PSR distribution law of narrow and long foundation pits obtained through 3D refined simulation,the analysis results of the entire 3D model can be inferred,thereby greatly improving the analysis efficiency.The new method solves the problem of traditional finite element analysis where overly simplified simulations cannot reflect the complex characteristics of foundation pits,while overly refined simulations resulting in high modeling costs and low analysis efficiency,making it difficult to meet the timeliness requirements of design scheme changes and construction risk prediction.It provides a new approach for finite element analysis.