地铁车站深基坑变形特性和突涌判定数值分析

A Numerical Analysis of Deformation Characteristics and Gushing Determination of Deep Foundation Pit in Metro Station

针对常州青枫公园地铁车站深基坑工程,研究了深基坑开挖对围护结构和周围土体变形的影响,并对比了土体小应变硬化土模型数值模拟和现场监测结果,以及数值模拟和压力平衡法对基坑突涌的判定结果。研究表明:数值模拟结果的规律性符合现场实际和工程经验,计算结果与现场监测值较为接近;与传统压力平衡法相比,有限元数值模拟判定基坑突涌需要的降水深度更小,说明传统压力平衡法判定基坑突涌过于保守,基坑突涌判定应考虑土体抗剪强度的影响。

Aiming at the deep foundation pit project of Changzhou Qingfeng Park Metro Station,the influence of deep foundation pit excavation on retaining structure and surrounding soil deformation is studied.The numerical simulation and field monitoring results of small strain hardened soil model of soil are compared,and the judgment results of foundation pit gushing by numerical simulation and pressure balance method are also compared.The results show that the regularity of numerical simulation results accords with the field practice and engineering experience,and the calculation results are close to the field monitoring values.Compared with the traditional pressure balance method,the dewatering depth needed to determine the foundation pit gushing by finite element numerical simulation is smaller,which indicates that the traditional pressure balance method is too conservative to determine the foundation pit gushing,and the influence of soil shear strength should be considered in the determination of foundation pit gushing.