变向水平加载下裙式吸力基础三维运动及周围砂土变形规律试验研究  

Mode test on three-dimensional motion mode of modified suction caisson under multidirectional horizontal loading and its surrounding sand deformation characteristics

作　　者：张雨坤[1] 杨逸飞 李大勇[1,2] Zhang Yukun;Yang Yijei;Li Dayong(Key Laboratory of Civil Engineering Disaster Prevention and Mitigation,Shandong University of Science and Technology,Qingdao 266590,China;China University of Petroleum,Qingdao 266580,China)

机构地区：[1]山东科技大学土木工程防灾减灾重点实验室,山东青岛266590 [2]中国石油大学(华东),山东青岛266580

出　　处：《土木工程学报》2024年第12期78-91,共14页China Civil Engineering Journal

基　　金：国家自然科学基金(51808325,51879044);山东省高等学校青年创新团队支持计划。

摘　　要：海上风电基础长期受到水平风、波浪荷载作用,荷载方向随季节和气象变化显著,影响基础安全服役。裙式吸力基础是海上风电新型基础形式,开展模型试验,研究其在变向水平单调荷载下三维运动及砂土表面变形规律。研究表明:水平荷载方向改变之后,裙式吸力基础运动方向并非始终与加载方向一致,基础运动模式分为三个阶段,第一阶段主要发生基础水平面内转角的改变(水平面内即扭转运动),第二阶段基础水平面内转角与竖直方向倾角变化程度相近,第三阶段主要发生竖直方向倾角的改变。加载方向改变后,裙式吸力基础在水平面内运动方向随水平荷载的增加由初始加载方向逐渐向水平荷载加载方向偏移,即水平面内运动轨迹变化具有“滞后性”,且裙式吸力基础比传统吸力基础“滞后性”更加明显,表明变向水平荷载作用下裙式吸力基础有更强的稳定性。荷载方向改变后,基础周围土体表面变形范围不规则、沿水平加载方向不对称,不对称性主要表现在初始加载方向前侧和后侧,且当荷载偏转角度为90°时,不对称性最明显。裙式吸力基础周围土体表面变形范围大于传统吸力基础,最大为传统吸力基础的1.60倍;裙式吸力基础前后侧土体表面变形范围之比小于传统吸力基础。Offshore wind turbine foundations are subjected to the horizontal loads induced by wind and wave during service life,and the directions of the horizontal loads vary prominently with the changes of seasons and oceanic weathers.Modified suction caisson(MSC)is an innovative foundation for offshore wind turbines,and model tests are carried out to investigate the three-dimensional motion mode of MSC under multidirectional horizontal loading and its surrounding sand deformation characteristics.Test results show that under multidirectional horizontal loading,the motion direction of MSC does not always coincide with the loading direction.Furthermore,the motion mode of MSC after the change of the loading direction can be divided into three stages.In the first stage,MSC may change its tortional angle in the horizontal plane,mainly presenting torsional motion of MSC;in the second stage,the changes in the torsional motion in the horizontal plane and the inclination angle in the vertical plane of MSC are close;in the third stage,MSC may mainly present the change in the inclination angle in the vertical plane.After the change of the loading direction,the motion direction of MSC in the horizontal plane gradually tends to the loading direction from the initially loading direction,disclosing the hysteresis phenomenon of the motion locus.Particularly,the hysteresis phenomenon of MSC is more prominent than that of the regular suction caisson(RSC),indicating that MSC is superior to RSC in stability.After the change of loading direction,the deformation range of the sand at the ground surface around the caisson becomes irregular and asymmetric,and the asymmetric phenomenon is mainly present at the front and back sides along the initial loading direction.The asymmetric phenomenon is most pronounced for the loading variation angle of 90°.The deformation range of the sand at the ground surface around MSC is greater than that around RSC,with the maximum of 1.61 times that of the RSC.

关 键 词：裙式吸力基础 变向水平加载 模型试验 基础三维运动 土体变形 

分 类 号：TU470.3[建筑科学—结构工程]