The monopile foundation of offshore wind turbines is subjected to cyclic loads such as wind
waves and currents for a long time
resulting in excessive cumulative deformation of the pile foundation. The monopile foundation is strengthened in the shallow layer with cement-soil to form a composite pile
so as to achieve the purpose of reducing the cyclic cumulative deformation. To research the cyclic behavior of monopile in cement-improved clay
a series of model tests on the lateral bearing capacity of monopile in cement-improved clay under lateral cyclic loading were carried out. The variation characteristics of monopile bearing capacity
pile bending moment
accumulated deformation
cyclic unloading stiffness and cyclic bending moment before and after reinforcement were analyzed. The test results show that the initial stiffness and ultimate bearing capacity of single pile are significantly strengthened by cement-improved soil
and the maximum bending moment of pile is reduced
which improves the overall load performance of pile. Regardless of the reinforced or the unreinforced pile
with the increase of cycle times
the cumulative displacement of pile top cycle increases rapidly initially
and then gradually stabilizes. Cement-soil reinforcement can effectively improve the horizontal stiffness of pile foundation
but it cannot change the law of attenuation with the increase of circulating load amplitude. There is a significant accumulation of the bending moment of the unreinforced pile
but the cumulative effect of the decrease of the reinforced pile can be ignored.
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