桶式基础吸力沉贯试验研究

RESEARCH ON SUCTION PENETRATION TEST OF BUCKET FOUNDATION

针对海上风电场单桶多隔舱基础开展沉贯试验研究,并通过土压计、应力计等科研传感器数据对基础沉贯阻力和侧壁变形进行分析。自重下沉阶段基础最大倾角约为1.2°,吸力下沉阶段初期将基础调平后,不再发生显著倾斜。对淤泥质土层中的钢制桶式基础,采用静力触探数据结合上限阻力系数获得的理论压差结果与实测值最为接近,并基于实测土压力获得了侧壁摩擦系数为0.23。施工期结构应力监测结果表明,最大应力发生于桶顶,侧壁在压差作用下发生显著挠曲。基于单桶多隔舱基础吸力沉贯过程中隔舱内压力基本保持一致的现象,提出一种将应力计布设于隔舱板,从而避免内外压差影响的传感器布设方案。

A suction penetration test of offshore wind farm multi-compartment bucket foundation is carried out.The pressure difference,earth pressure and structural stress are monitored during the penetration test,based on which the penetration resistance and side wall deformation are analyzed.Field test results indicate that,the maximum foundation inclination is about 1.2°in the self-weight penetration stage.After the bucket foundation being leveled at the initial stage of suction penetration,the foundation no longer tilts significantly.For steel bucket foundations in muddy soil,the theoretical pressure difference calculated based on cone penetration test(CPT)data with upper bound value of resistance coefficient used in calculation is the closest to the measured result.A sidewall friction coefficient of 0.23 is obtained based on the measured earth pressure.The structure stress monitoring results of the bucket foundation during construction period indicates that the maximum stress occurs at the bucket top plate,and the side wall deflects significantly as a result of the pressure difference.Based on the phenomenon that the water pressure in the compartments are basically consistent during the suction penetration stage,a sensor layout scheme is proposed,in which the stress gauge is arranged on the compartment plate to avoid the influence of difference between internal and external pressures.