Abstract: liquefaction and sand boiling are common failure phenomenon during the suction penetration for bucket foundation. However, the jacked penetration can avoid such failure phenomenon. The jacked penetration tests of bucket foundation with different sizes is designed in the laboratory. The earth pressure internal and outer the bucket body is discussed in the process of penetration, meanwhile, the soil displacement field is obtained by using digital image processing technology. Test results show that the soil plugging effect of bucket foundation appears when the penetration depth reached 1 times of the diameter of bucket, and the incremental filling ratio of soil plug is about 0.7 after penetration. The penetration resistance and the inner earth pressure of bucket increase linearly with the penetration depth during the penetration, then exponentially grow when the penetration depth reaches half times of the height of bucket shirt. The soil plug is more effective with 10 cm in diameter of bucket, and the height of soil plug is 15 cm. There is a soil arching effect inside the bucket, a passive soil arch is formed first at the end of bucket, then destroyed as the penetration depth increase, and the active soil arch form.

Key words: bucket foundation, jacked penetration, penetration process, soil plugging effect, model test