邻近建筑物超载时深基坑施工变形特性研究

Construction deformation characteristics of foundation pits under adj acent overloading buildings

由于深基坑周围环境的多样性,土体及支护结构的变形规律变得复杂。在土的弹塑性模型基础上,考虑时间的影响,引入滞后塑性变形的概念,将非弹性应变分解为瞬时塑性应变和滞后塑性应变,发展一个描述软土蠕变特性的弹黏塑性模型,通过FLAC^(3D)平台,进行二次开发。对某地铁车站深基坑施工进行了三维数值模拟,通过各工况下土体的变形矢量及墙体测斜值的分析,并与相同条件下无超载时作比较,探索邻近建筑物超载作用下深基坑施工土体的变形规律。

The deformation pattern of the soil mass and supporting system is quite complex due to the diversity of the surrounding environment.On the basis of elastic-plastic constitutive model,an elastic-viscose-plastic constructive model was developed.It could explain the creep characteristics of soft clay by introducing a hysteretic deformation item decomposing the non-elastic strain into instantaneous plastic strain and hysteretic plastic strain with the help of the secondary development program interface provided by FLAC^(3D),and numerical analysis of the constructive model was implemented.Three-dimensional numerical analysis was carried out towards the station.By means of deformation vectors and inclination survey analysis,the deformation pattern under the surrounding overload was studied and compared with that under non-overload conditions.