船舶撞击近海风机群桩基础的离心模型试验  

Centrifuge tests of ship impact on pile groups beneath offshore wind turbines

作　　者：孔令刚[1,2] 余佳 陈云敏[1,2] KONG Ling-gang;YU Jia;CHEN Yun-min(Institute of Geotechnical Engineering,Zhejiang University,Hangzhou 310058,China;Key Laboratory of Soft Soils and Geoenvironmental Engineering of Ministry of Education,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江大学岩土工程研究所,浙江杭州310058 [2]浙江大学软弱土与环境土工教育部重点实验室,浙江杭州310058

出　　处：《浙江大学学报（工学版）》2023年第2期330-339,共10页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(51579218);国家自然科学基金基础科学中心资助项目(51988101)。

摘　　要：建立船舶撞击近海风机群桩基础的离心模拟系统.在饱和密砂中开展了4组2×2群桩的撞击试验,包括水平撞击和撞击点距承台中心4.5倍桩径的水平偏心撞击群桩基础试验以及水平撞击和水平偏心撞击装有上部风机的群桩基础试验.重点考察承台上部风机存在与否以及船舶撞击位置对船舶撞击力和群桩基础动力响应的影响.试验结果表明,风机与群桩基础之间存在明显动力相互作用.承台的振动带动风机发生水平摆动和扭转振动;风机分担和消耗一部分经船舶撞击传递给群桩基础的能量,导致在自由振动阶段承台的振幅快速衰减.撞击承台的位置对撞击力和群桩内力有明显影响.对比水平和水平偏心撞击群桩试验,虽然偏心撞击工况下的撞击速度比水平撞击工况下的大26%,但偏心撞击的撞击力峰值比水平撞击的小20%;在群桩受偏心撞击工况下各基桩桩头弯矩峰值相差最大达3.2倍.偏心撞击更易引发群桩破坏.An onboard system was built to simulate ship impact on the pile group foundation of offshore wind turbines. Four centrifugal model tests on a 2×2 pile group were conducted in saturated dense sand, including the tests on pile groups with and without an upper wind turbine subjected to lateral impact or eccentric impact with an eccentricity of 4.5 times pile diameters. The influence of the exist of wind turbine on top of pile cap and the impacted position by ship on pile cap on the impact force and the dynamic response of pile groups was investigated. Data from the model tests showed that strong dynamic interaction existed between the wind turbine and its underlying pile group. The motion of the pile cap made the wind turbine cause both lateral and torsional vibrations. The wind turbine shared and dissipated part of the energy transferred from the ship, which made the acceleration amplitudes of the pile cap attenuate quickly in the free vibration phase. In addition, the impact position on pile cap significantly affected the impact force and the internal forces of the group piles. The measured peak impact force from the test on the pile group without wind turbine subjected to eccentric impact was 20% smaller than that from the test on the pile group subjected to lateral impact, and the impact velocity in the former test was 26% higher than that in the latter. The maximum ratio of the peak pile-head bending moments of the piles was 3.2 in the test on the pile group without wind turbine subjected to eccentric impact. Generally, comparing with lateral impact on pile cap by ship, eccentric impact is more critical to make a pile group fail.

关 键 词：群桩 近海风机 水平偏心撞击 动力响应 离心试验 

分 类 号：TU47[建筑科学—结构工程]