下穿高架桥的地铁基坑监测及分析

Monitoring Analysis of Metro Station Excavation under Crossing Viaduct

介绍了无锡地铁1号线金城路站基坑围护设计、监测方案,分析了监测数据,得出了下穿高架桥段基坑开挖过程中桩体的变形、基坑周边地表沉降、支撑轴力、临时立柱及高架桥墩竖向位移的变化规律:桩体变形呈"大肚状",最大深层水平位移出现在坑底浇筑完毕时;地表沉降变化受开挖速度和支撑架设影响,最大变化量发生在距离开挖深度的0.6倍左右处;支撑体系有足够的安全储备且偏于保守.由监测结果可知,围护、监测方案可行,确保了基坑工程及高架桥的安全.

The containment design and the monitoring scheme for foundation pit engineering in Jincheng Road stop of Wuxi metro line 1 is introduced; and the monitoring data is analyzed; then the change rule of pile body＇s deformation, ground surface settlement around the pile body, axial force of the support, vertical displacement of temporary upright and viaduct piers during excavating the foundation pit are obtained. The shape of pile body＇s deformation looks like big belly; and the maximum displacement appears at the bottom of the foun- dation pit when the pouring is finished. The excavation speed and set-up of the support have a significant in- fluence on the change of ground surface settlement; the maximum variable quantity appears at 0.6 times far from the excavation depth. The support system has sufficient emergency capacity. As a result, the scheme of containment and monitoring are feasible. The foundation pit engineering and the viaduct are both under safe state.