During pile driving soil adjacent to pile tip comes into the tubular pile thus formed soil plug. The effect of soil plug on the bearing capacity of large-diameter steel pipe pile and new developed large-diameter cast-in-situ tubular pile can not be neglected. Through soil plugging the bearing capacity of open-ended pile will be increased and its settlement decreased. Two different definition of soil plugging were compared

and through which the definition based on the failure mechanism was verified to be more reasonable. Different effects

such as pile diameter

inner friction

vertical bearing capacity of the underlain soils and the lateral stress level

were studied. ICP discriminant of plugging mode for both clay and sand was discussed. This method was proved to be a simple one and cannot embody the real plugging in practice.