HSS模型在某基坑变形分析中的应用研究

Research on Application of HSS Model in Deformation Analysis of a Foundation Pit

摘要:

随着城市的发展，城市用地空间日益紧张，基坑开挖支护受空间地形限制，对周边结构造成较大影响。为有效降低基坑开挖对周边环境的影响，结合工程情况，利用现状挡墙结构进行骑跨式加固改造，并在墙后新建SMW（soil mixed wall）工法桩支护作为围护结构，建立Plaxis有限元模型，采用HSS（hardening soil with small strain stiffness）模型对基坑开挖过程中引起的周边环境位移进行数值模拟。结果表明，该方法有效可行，能够减少现状结构拆除量，施工引起周边环境位移在允许范围之内。相较于一般土体本构模型，基于HSS模型的基坑变形数值模拟结果偏安全，更接近监测值，具有一定的工程意义。

Abstract:

With the urban development, the urban land space is becoming increasingly tight. The excavation and support of foundation pit are limited by spatial topography, which will significantly affect the surrounding structures. To effectively reduce the impact of foundation pit excavation on the adjacent environment, combined with the engineering conditions, the existing retaining wall structure is utilized to conduct a straddle-type reinforcement and reconstruction, and a SMW (soil mixed wall) pile support is newly constructed behind the wall as the enclosing structure. A finite element model of Plaxis is established, and the HSS (hardening soil with small strain stiffness) model is adopted to perform numerical simulations of the surrounding environmental displacement caused by the foundation pit excavation. The results indicate that the proposed method is feasible, which can reduce the volume of demolition required for the existing structure, and the surrounding environmental displacement caused by the construction is within the allowable range. Compared with conventional soil constitutive models, the numerical simulation results of foundation pit deformation based on the HSS model are relatively safe and closer to the monitored values, which has certain engineering significance.