ABSTRACT
Tetrapod piled jacket (TPJ) foundations have been widely used in offshore wind farms due to their advantages of rigidity and influence by wave action. This paper compares centrifuge model tests of TPJ foundation in saturated sand and in normally consolidated clay when subjected to lateral monotonic loads. It is found that the depth of maximum bending moment and inflection point in sand are obviously shallower than that in soft clay. Based on the distribution curve of lateral pile displacement derived from the bending moment, limited pile deflection in sand can be observed below a depth of approximately 7D (D denotes pile diameter), while this value is about 12D in clay. The soil resistance around back row piles is about 40% of the front row piles in sand since the increase of axial force in piles could change the effective stress around the piles, while that difference is not significant for the undrained soft clay. The failure of TPJ foundation under lateral static loads is due to the back row piles pulling out both in sand and clay, as observed from the vertical load-displacement curves of the piles.
