Performance of a pile foundation in soft soil

This paper presents the field instrumentation on the pile foundation of the 492 m high Shanghai World Financial Centre (SWFC), which is supported on steel pipe piles of 700 mm dia. and 60 m long in the deep, soft soil of the Yangtze River delta. During the whole construction stage, the performance of the pile foundation, including pile load, contact pressure, pore-water pressure and settlement, was intensively and successfully investigated. The monitored data indicated that the force acting on the pile, in stark contrast to the design assumption of loading equally, was quite uneven; the contact pressure inevitably was produced once the settlement developed; the pore-water pressure reflected the water head from the underground confined water; the foundation settlement was 127 mm and the settlement difference was 6 mm between the opposite sides of the raft. The analytical work demonstrates the influence of the various factors contributing to the observed behaviours of the foundation, and the safety of the observed foundation is still under control. For the first time, in situ testing of the pile foundation of a super-tall building embedded in deep, soft soil was conducted; the results provide a comprehensive insight into the working performance of a pile foundation.