浅析城市核心区复杂环境条件下超大超深基坑开挖技术

Analysis of excavation technology for super large and deep foundation pit under complex environment in urban core area

上海某超高超大综合体工程位于城市核心区,基坑面积大,开挖深度超过30m,具有周围环境复杂、施工场地狭小,工期紧张等特点,且地铁9号线横穿场地北侧基坑,地铁11号线紧贴场地东侧基坑,土方开挖施工难度大。针对上述情况,通过在首道支撑上设置栈桥作为施工道路,采用分区、分层、分块、限时、对称方式进行土方开挖,降低了土方开挖难度;合理组织机械和劳动力,及时形成支撑,加快了施工进度;并在基坑施工过程中实施动态全方位的基坑监测,及时调整施工工况,控制了基坑变形,保证了深大基坑施工安全。

A super big and high complex project in Shanghai is located in the core area of the city.The foundation pit area of the project is large and the excavation depth is more than 30m.It has the characteristics of complex surrounding environment,narrow construction site and short construction period.Moreover,Metro Line 9 crosses the foundation pit at the north side,and Metro Line 11 is close to the foundation pit at the east side.In view of the above situation,by setting trestle on the fi rst support as the construction road,the earthwork excavation is carried out in the way of partition,layering,block,time limit and symmetry,which reduces the diffi culty of excavation.Reasonably organizing machinery and labor force and forming support in time speed up the construction progress.Implementing dynamic and all-round foundation pit monitoring in the process of foundation pit construction,and timely adjusting the construction,the deformation of the foundation pit is controlled to ensure the construction safety of the deep and large foundation pit.