Abstract: A large number of floating piles in a project in the coastal soft soils were detected through the large strain dynamic pile loading tests on the prestressed concrete piles. The floating pile phenomena were comparatively studied by the various static axial loading tests and low strain tests. The potential factors that triggering the floating pile are discussed in the paper and the mitigation methods for the floating pile are proposed. The results indicate that when pipe piles are used in soft soil area, the high strain method can be used to preliminarily verify if a floating pile exists; In the case of deep silt soil layer, the pile type should be carefully selected in accordance with the local subsurface soil conditions; The restriking method can effectively mitigate the floating problem of pipe piles, and it is suggested to give priority to the free falling hammer re driving combined with high strain method monitoring in soft soil areas, which has important reference and reference significance for similar projects.

Key words: Soft Soil Area, Pipe Piles, Floating Pile Mitigation Method, Large Strain Dynamic Pile Loading Tests