海上风电单柱复合筒型基础吸力沉放特性研究

Research on the suction settlement characteristics of single-column composite bucket foundation for offshore wind power

单柱复合筒型基础作为一种新型海上风机基础结构,在中国海上风电抢装潮中得到了广泛的应用。针对单柱复合筒型基础在土体中的下沉特性,在室内进行了小比尺物理模型试验。试验中采用抽水负压下沉的方式,选取结构总重量作为主要变量,得出结构的下沉时程曲线,随着结构重量增加,结构下沉所需要的总时间减小,自重下沉阶段占比增加;总结了下沉过程中的结构倾角变化规律,入土瞬间倾角较大,自重下沉阶段结构的倾斜情况受土质均匀性的影响表现得比较复杂,仅通过抽水阀门的调节倾角难以恢复,负压调平效果明显;得出下沉过程中舱内孔隙水压力的变化规律,舱内孔隙水压力随下沉过程逐渐减小,自重下沉阶段孔隙水压力对土体扰动相对较小;土体中下沉渗流减阻效果十分明显,渗流方向为自舱外沿筒底部流向舱内。

The single-column composite bucket foundation,as a new type of offshore wind turbine foundation structure,has been widely used in Chinas offshore wind power installation surge.In order to investigate the settlement characteristics of the single-column composite bucket foundation in sandy soil,small-scale physical model tests were conducted indoors.During the experiments,the method of suction negative pressure sinking was employed,with the total weight of the structure selected as the main variable.The sinking time history curve of the structure was obtained,showing that as the structure weight increases,the total time required for sinking decreases,with the self-weight sinking stage proportion increasing.The variation law of the structure inclination angle during the sinking process was summarized.The inclination angle is relatively large at the moment of soil entry,and the inclination situation of the structure during the self-weight sinking stage is affected by the uniformity of the soil,showing a relatively complex pattern that is difficult to recover the inclination angle only by adjusting the suction valve,but with a noticeable effect of negative pressure leveling.The variation law of the pore water pressure inside the chamber during the sinking process was determined,showing a gradual decrease in pore water pressure inside the chamber as the sinking progresses,with relatively minor disturbances to the soil during the self-weight sinking stage.The resistance reduction effect of sinking seepage in sandy soil is very obvious,with the seepage flowing from the outside of the chamber along the bottom of the tube towards the inside.