Abstract：Based on the in-situ load tests, the load-bearing behavior of large-diameter belled PHC pipe piles by NAKS-construction-method in soft soil area is studied. In case of the same pile radius and the pile length, the ultimate bearing capacity of the large-diameter belled PHC pipe piles accounts for that of the hammer piles 90%, and is 1.3 times larger than that of the bored piles. The results show that the load carrying curves of most piles vary gradually, and the ultimate bearing capacity of the piles is determined by the displacement of the pile head. About 40%~50% of the loads at pile tips is shared by the axial force at pile top under the ultimate bearing capacity. The piles behave as end-bearing friction ones, and the ultimate bearing capacity is higher. The research results can provide reference for the research and application of large-diameter belled PHC pipe pile by NAKS-construction-method in soft soil area.
