Experiment and analysis on penetration of suction bucket foundation

As a new type of foundation, the suction bucket foundation has good technical and economic performances compared with traditional foundations. The key construction parameter, soil plug, and construction efficiency are analyzed through model tests of a suction bucket foundation in silty clay with different suction pressures applied. Measured suction pressure in tests with different suction pressure applying patterns are between the required value and the critical value calculated by the DNV standard. The suction pressure in suction releasing pattern is larger than that in suction maintaining pattern for suction bucket to reach the same depth. In addition, the least soil plug degree is obtained in the suction releasing pattern with a large suction pressure increment, provided penetration efficiency is assured. Theoretical analysis shows that the inside friction resistance increases with the gradient of inside pressure along depth and large friction resistance restricts the formation of soil plug. The mechanism of reduced soil plug in suction releasing pattern is explained by the excess pore water pressure results. The earth pressure results show that the normal effective stress mobilized on the bucket wall in the suction releasing pattern is larger than that in the suction maintaining pattern. Accordingly, the side friction mobilized of the former is also larger.