| Although p-y method has been widely used in the design of laterally loaded monopiles, it has been questioned in the design of super large diameter monopiles used in offshore wind turbine. Current researches suggest that this question is caused by the dimensional effect. Based on the three-dimensional numerical simulation technology, this paper carries out the development of the soil resistance on the laterally loaded monopiles driven in sand and discuss the main disadvantages and reasons in the design of super large monopiles. The numerical simulation results convince that the super large monopile foundations' soil-monopile interaction has obvious three-dimensional effect, owing to large monopile diameter and little length-to-diameter ratio ( the ratio of the embedded length to the monopile diameter). In addition to the soil lateral resistance, super large monopiles bear the horizontal shear force developed at the base of monopile, the friction force and the resistance moment generated by the unbalanced reaction force along the monopile shaft. The latter three resistances' contribution to lateral bearing capacity is related to the monopile size. The large diameter and little length-to-diameter ratio increase the contribution of these three resistances. In the process of calculating and analyzing the bearing characteristics of laterally loaded monopile, in addition to the resistance provided by the soil lateral reaction (represented by p-y springs), the horizontal shear force developed at the base of monopile, the friction force and the resistance moment generated by the unbalanced reaction force along the monopile shaft shall also be considered. |
