水平单调荷载作用下饱和细砂中裙式吸力基础土压力特性分析

Earth pressure distribution of skirted suction caissons embedded in saturated fine sand under monotonic lateral loading

吸力基础具有造价低、施工速度快、可重复利用等优点,因此被广泛应用于海洋工程领域,近年来也受到海上风电工程的重视。作为海上风电基础,主控荷载为水平荷载。为提高基础的水平承载能力并有效限制其侧移,以保证风机正常运行,提出一种改进的吸力基础型式-裙式吸力基础。通过饱和细砂中裙式吸力基础水平单调加载模型试验,探究基础周围土压力分布的影响因素,利用土压力增量方法,可以合理确定基础转动点的位置,并揭示'裙'结构尺寸对转动点位置的影响。相比于传统吸力基础,裙式吸力基础水平承载力提高,主桶结构前侧所受被动土压力减小,后侧所受被动土压力增大;裙式吸力基础转动点位置在0.54~0.67倍的基础埋深处,较传统吸力基础的转动点位置(位于0.71倍基础埋深)偏上,且随裙宽增加、裙高减小而上移。

Due to the cost effectiveness,rapid construction and repeatability,suction caissons are extensively used in offshore engineering. In offshore wind engineering,foundations are mainly subjected to lateral loads resulting from wind,waves,and currents. To increase the lateral bearing capacity and reduce the lateral deflection of the foundation,a novel type of the suction caisson,the skirted suction caisson,is proposed. Earth pressures along the length of the skirted suction caissons embedded in saturated fine marine sand were investigated by a series of small-scale mode tests. The rotation centers of the suction caisson was determined using the earth pressure increment distribution method. Different from the traditional suction caisson,for the skirted suction caisson,passive earth pressures acting on the main structure in the loading direction decrease,while those opposite the loading direction increase. The rotation center of skirted suction caisson is located at between 0. 54 and 0. 67 embedded depth of the foundation,which is higher than that of the traditional suction caisson( its rotation center is located at 0. 71 embedded depth). The rotation center of the skirted suction caisson moves upwards when the skirted width increases or the skirted depth decreases.