Development and Influence of Pore Pressure around a Bucket Foundation in Silty Soil

Silty soil is common in the seabed of eastern coastal areas of China. The behaviors of the silty soil and a bucket foundation installed within it need more study. In this work, model tests of a bucket foundation in silty soil were performed. The development of the excess pore water pressures in the different positions around the bucket was measured. Different loading conditions, with a change in the horizontal cyclic load amplitude ratio, horizontal cyclic frequency, and vertical load ratio, were considered. The effects of the pore water pressure on the shear strength of the soil around the bucket and the horizontal bearing capacity of the bucket foundation were investigated. The results show that the normalized pore water pressures close to the bucket wall at depths between 0.1 L and 0.3 L exhibit distinct change under the cyclic load. Consistent with the distribution of the pore water pressure, the degradation of the undrained shear strength is more obvious with a greater load amplitude ratio, a greater load frequency, and a smaller vertical load. The degradation rate of the static horizontal ultimate bearing capacity is in a range of 1.57% to 14.90%, under different loading conditions.