Key construction techniques for oversized excavation pits using top-down method

The deep foundation pit of the headquarter base of Tangdong central block in Lujiazui of Shanghai is constructed by use of the top-down method. It is a very distinctive engineering case in this area. Some key design and construction techniques are introduced. They include rational planning of soil excavation, treatment of critical construction nodes and control of uneven settlement, etc. The success of this case may provide engineering experience for similar projects.