Abstract: The complexity and uncertainty of the soft ground have great influence on the support engineering of deep foundation pit. With regard to a project in the Pearl River Delta under bad geological conditions, it presents a monitoring design in detail. A comprehensive analysis of the monitoring data, such as the horizontal displacement of retaining structures, underground water levels, axial forces of struts, and surface settlement, has been conducted to get some valuable deformation laws to ensure the quality of the foundation pit construction as well as the safety of the surrounding buildings. The influencing factors of the foundation pit supporting structure and the surrounding deformation have also been analyzed. 

Key words: soft foundation; deep foundation pit; monitoring