绍兴地铁一号线深基坑开挖过程数值分析

Numerical Analysis of Deep Foundation Pit Excavation Process of Shaoxing Subway Line 1

以绍兴地铁一号线工程为背景,建立大型三维有限元模型,对该地铁深基坑的开挖及地下连续墙、钢支撑等支护结构体系的位移变化进行数值模拟,并对比模拟结果与现场监测数据。结果表明:地下连续墙的最大水平位移与现场实测值误差仅为8%,基坑周边土体的竖向位移即沉降与现场实测值误差较大;对于长宽比较大的深基坑,地下连续墙长边中点和端部2个断面的变形相对其他位置的较大,应单独设置合理的报警值;开挖层的上一层钢支撑轴力会显著增加,是设计和施工需要密切关注的一个焦点。

Taking Shaoxing Subway Line 1 project as background,a large three-dimensional finite element model was established to numerically simulate excavation of the subway deep foundation pits and displacement variation of supporting structure system such as underground diaphragm walls and steel supports.Simulation results were compared with on-site monitoring data.The results show that the error between the maximum horizontal displacement of the underground diaphragm walls and the on-site measured values is only 8%,while the error between the vertical displacement(settlement)of soil surrounding the foundation pits and the on-site measured values is larger.For deep foundation pits with larger length-width ratio,the deformation of two sections at the middle point and the end of the long side of the underground diaphragm walls is larger than that at other positions,so a reasonable alarm value should be set separately.The strut axial force of steel in the layer above the excavation layer will increase significantly,which should be a focus that needs to be paid close attention in design and construction.