Abstract: During the construction of Ningbo rail transit, a new type of pile foundation  JZGZ pile was adopted. When the borehole is drilled to the designed elevation, the base of the current segment is expanded and then the cement slurry is injected and mixed with the soil; finally, the prefabricated pile is installed with enlarged joints. The JZGZ pile combines the advantages of drilled pile, prefabricated pile and deepmixing column. Its bearing capacity can be improved remarkably. In this paper, the selfbalanced method is applied to the vertical bearing capacity testing of the two JZGZ piles. It is concluded that the selfbalanced method is suitable for the JZGZ pile static load test. The measured results indicate that the axial capacity of the test piles met the design requirements. The loadsettlement curves of the two piles are roughly liner, and it shows that the JZGZ pile has good axial capacity.

Key words: JZGZ Pile, Pile Axial Capacity, Selfbalanced Load Test Method