Abstract: Pipe pile supported foundations are widely used in engineering construction due to its advantages of having large bearing capacity, small settlement, reliable pile quality and fast installations. More and more projects utilize the pipe pile supported composite foundations to control the settlement. However, using the pipe pile foundations as a settlement controlling measure in foundations in soft soils with deep excavation that requiring the internal strut supports is limited due to the constraints of construction equipment and space. This paper presents a case history of an underground roadway project in Qianhai, Shenzhen City. The influence of pipe pile installation inside of the deep excavation area on the lateral deflection of the supporting structure was evaluated through the numerical analysis using commercial software MIDAS. The analytical results are also compared with the site monitoring results. It is concluded that the pipe pile installation inside the deep excavation area could contribute the lateral deflection control.

Key words: pipe pile composite foundations, deep excavation in soft soils, supporting structures, influence analysis