风机荷载作用下频率比对砂土动力响应的影响  

Effect of Frequency Ratio on Dynamic Responses of Sand Under Wind Turbine Loading

作　　者：张艳 贾敏才[1,2] 蒋明镜[1,3,4] 谢志伟 ZHANG Yan;JIA Mincai;JIANG Mingjing;XIE Zhiwei(College of Civil Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education,Tongji University,Shanghai 200092,China;State Key Laboratory of Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China;School of Civil Engineering,Suzhou University of Science and Technology,Suzhou 215009,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092 [3]同济大学土木工程防灾减灾全国重点实验室,上海200092 [4]苏州科技大学土木工程学院,江苏苏州215009

出　　处：《同济大学学报（自然科学版）》2024年第5期738-748,共11页Journal of Tongji University:Natural Science

基　　金：国家自然科学基金(51639008,51890911);同济大学土木工程防灾国家重点实验室自主课题(SL⁃DRCE19-A-06);海南省重点研发计划(ZDYF2021SHFZ264)。

摘　　要：海上风机在运行过程中风荷载与波浪荷载频率耦合作用对土体动力特性的影响不容忽略,为了探究这种影响,采用多向循环动单剪系统(VDDCSS)对砂土进行了一系列试验研究,分析了双向剪切频率比f_(r)对砂土动应变、动孔压比以及动强度的影响。试验结果表明:剪应变发展受双向频率耦合及应力组合效应的影响。循环应力比(C_(SR))为0.15时,双向频率耦合效应大于应力组合作用;随着应力水平的增加(C_(SR)=0.20或0.25),频率耦合效应和应力组合作用均得到了加强。在低应力水平时,破坏试样的孔压曲线呈“上凹型”且频率比对试样孔压发展影响不大。而随着应力水平增加(C_(SR)=0.20或0.25),孔压最终值u_(max)随之增大。除f_(r)=1.00与10.00对应试样外,土体动强度随f_(r)与C_(SR)值增大而减少。f_(r)=5.00对应试样应变大、孔压值高、强度低的原因与此比值下土体受双向频率耦合与应力组合的叠加效果增强有关。The soil sample is subjected to a coupling effect of wind and wave action with various frequencies during the operation of offshore wind turbines.A series of tests were conducted to investigate the influence of the frequency ratio between wind and wave loads on sand using a multi-directional cyclic simple system(VDDCSS).The effect of frequency ratio on the dynamic strain,pore water pressure,and dynamic strength of sand was analyzed.The test results show that the development of shear strain is affected by the bidirectional frequency coupling and the combination of x and y-direction stress caused by the frequency ratio.At a C_(SR) of 0.15,the bidirectional frequency coupling effect is greater than the stress combination effect.With the increase of the stress level(at a C_(SR) of 0.20 or 0.25),both the frequency coupling effect and the stress combination effect are strengthened.At a low-stress level,the pore pressure curve of the failed specimen is"upward concave"and the frequency ratio has little effect on the pore pressure development of other specimens.As the stress level increases(at a C_(SR) of 0.20 or 0.25),the final value of pore pressure u_(max) increases with increasing C_(SR).Except for the samples corresponding to a fr of 1.00 and 10.00,the dynamic strength of others soil samples decreases with the increase of f_(r) and C_(SR).At a f_(r) of 5.00,the sample has a large strain,a high pore pressure value,and a low dynamic strength,which is related to the superposition effect of the two-way frequency coupling and stress combination.

关 键 词：循环单剪 频率比 动应变 动孔压 动强度 

分 类 号：TU4[建筑科学—土工工程]