Research On The Design,Construction And Site Management Of Deep Foundation Pit Support

In the 21 st century,the urban land resources in China become rarer and rarer,so the buildings throughout the country,as well as extending upward in height,are also extending downward in depth.The higher a building,the deeper its foundation would relatively be.For this reason,regardless of their extension direction the foundation pit of the buildings becomes deeper and deeper and the magnitude of foundation pit excavation grows larger and larger,with diminishing ground space around the foundation pit available for construction activities.Hence,the requirements for deep foundation pit support become ever more rigorous.At the present time,deep foundation support theory in China lags way behind the engineering practice,so continuous research,application,and management with regard to deep foundation pit support technology are very essential.This artical,based on a Plaza works in Nantong,provides a systematic description of the key points in various stages such as design,construction,and site management involved in deep foundation pit support works,analyzes the factors having an impact upon the support works during each stage,and summarizes successful design and construction experiences of deep foundation pit support in different construction environments and geological conditions,thus offering theoretical bases and references useful to the design and construction of similar deep foundation pits and being of great significance to ensuring work quality and their safe and economic completion.This artical draws on domestic and foreign developments and focuses on the scope and engineering characteristics of deep foundation pit works.Deep foundation pit works are identified with such characteristics as high risks,regional variation,uncertainty,and complexity.Three major support structure systems being distinguished in deep foundation pit design,this paper specifically discusses the selection of the three major support structures: earth-retaining and envelope,support,and waterproof curtain and also points out the intimate combinational relationship among them.The design case and design calculation notes are described in more details,which integrate the theory with the practice.With respect to management in deep foundation pit works,the focus is on the role foundation pit monitoring plays in management,on the issues to be aware of in management,and on the optimization measures.