Experimental investigation on seabed response characteristics considering vibration effect of offshore monopile foundation

Abstract

Monopile foundations are currently the most significant support form for offshore wind turbines. An experimental investigation of the vibrating monopile was conducted inside the cohesionless saturated sand bed to examine the pore water pressure oscillation response law and amplitude variation features around the monopile under the vibration effect. The experimental results indicate that the vibration loading force Fp, vibration frequency fv and vibration amplitude Av have remarkable impacts on the various characteristics of the pore pressure response around the monopile foundation. The lower the vibration frequency, the more prominent is the delayed attenuation process during the oscillation cycle, and a succession of pore pressure sub-peaks develop near the phase end of the cycle period. Additionally, the pore pressure amplitude decay rate increases with increasing frequency as the depth of the seabed grows, and the pile side pore pressure shows a trend of increasing and then decreasing with frequency.