紧贴地铁车站单侧深基坑的施工方案对比研究

Study on Construction Scheme of One-side Foundation Pit Engineering Adjacent to Metro Station

为有效控制单侧深基坑施工对紧贴地铁车站的变形影响,保护地铁车站的结构安全,以某紧贴地铁车站的深基坑工程为背景,采用三维有限元法数值分析手段,动态模拟了该深基坑工程的施工全过程,模拟结果与现场实测数据较为一致。然后在此基础上,针对深基坑的多种施工方案进行了系统的三维数值模拟对比分析。结果表明,对下伏地层为岩层的深基坑工程,深基坑单侧分区开挖相比不分区开挖能减少地铁结构的变形,虽量值较小但其总体上减小的规律依然存在;地铁车站结构底板竖向变形近基坑端大于远基坑端,认为地铁车站结构的遮拦作用对于岩层地区依然适用;基坑采取分区开挖措施和及时进行靠近地铁侧的基底反压措施可有效抑制地铁车站结构的变形。

In order to effectively control the deformation of metro station due to the one-side foundation excavation, and to secure the safety and normal use of metro, one actual deep foundation pit adjacent to metro is taken as background for study. Using 3D finite element method to simulate the actual process of one-side foundation pit excavation, it is found that the numerical prediction results coincide with measured values. Then, based on abovegiven, some construction schemes are comparatively analyzed by 3D numerical simulation in the systematic way. It indicates that the deformation of metro structure caused by zoned excavation is a little bit less than that caused by non-zoned ex- cavation in the rock layer. The value of deformation difference is so small, but the tendency of overall reduction still exists. The vertical deformation of metro floor near foundation side is larger than that of far away side. Zoned excavation and counter-pressure in foundation pit near metro can effectively control the deformation of metro structure.