Abstract

Plate–monopile hybrid foundations, as a potential alternative to monopiles, have demonstrated promising potential in enhancing load-bearing capacity and structural stability. To investigate its load transfer mechanisms and pile–soil interaction in clay, numerical models are developed under varying undrained shear strength (Su), pile diameter (D), and plate-to-pile diameter ratio (R). Through comparative analyses within different parameters configurations, the load-bearing capacity, pile deflection, bending moment and shear force distributions are systematically examined. The results indicate that: (1) Su, D and R are all positively correlated with the load-bearing capacity of the hybrid foundation, which can be expressed as the superposition of the monopile capacity and a quadratic function of R; (2) with increasing R, load transfer shifts from deep to shallow soil, accompanied by an upward pivot shift; increasing D causes a downward shift, more pronounced in weak soils; (3) for small-diameter hybrid foundation, the bending moment decreases progressively with increasing R, while for large-diameter, a stage-dependent response is observed, characterised by local moment concentration near the mudline within a certain range of R; (4) the shear force exhibits a double-peak pattern; increasing R strengthens the shallow peak and weakens the deep one, while increasing D localises the distribution near the mudline.

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