摘要
不同重现期的年极值冰厚是有冰海区建筑物设计的关键指标。目前在确定设计冰厚时,往往只给出点估计。而求解设计冰厚的置信区间,在某一置信水平下获取设计值的范围,可以确定设计重现值的不确定性,给海工结构物的设计与建造提供指导。采用极大似然方法区间估计,给出了Gumbel分布、三参数Weibull分布、三参数对数正态分布和P-III型分布置信区间的求解过程。利用渤海北部营口和葫芦岛海区历年总冰厚极大值的实测数据,基于以上4种分布型式,采用极大似然法求得不同重现期下冰厚重现值的置信区间,并对各分布型式进行了优选比较。结果表明,选取P-III型分布求解这两地海冰厚度重现值的置信区间较优。
Different return periods of annual extreme ice thickness are the key indexes for ocean structure design of ice-infested area. Only the point estimations of sea ice thickness have been given in the current practical engineering design. However, estimation of confidence intervals can consider the uncertainty of design values of sea ice thickness, which play an important role to provide guidance for the design and construction of marine structures. Based on the maximum likelihood method of interval estimation, the solving processes of confidence intervals are presented using Gumbel distribution, Weibull distribution with three parameters, log-normal distribution with three parameters and Pearson type III distribution. Taking the data of annual extreme floating ice thickness in the northern area of Bohai Sea as examples, the above four types of distributions are adopted to fit the observed data at Yingkou and Huludao. The confidence interval of the design ice thickness under different return periods are estimated by maximum likelihood method. The results show that the confidence intervals of the design sea ice thickness calculated by Pearson type III distribution are better than those by the other three distributions.
出处
《工程力学》
EI
CSCD
北大核心
2013年第7期294-298,共5页
Engineering Mechanics
基金
国家重点基础研究发展计划项目(2011CB013704)
国家自然科学基金项目(50579085)
关键词
海冰
海洋结构
冰厚重现值
置信区间
极值分布
sea ice
marine structure
return sea ice thickness
confidence interval
extreme value distribution