ERA5海面气压和风速再分析资料在渤海和北黄海适用性分析

利用渤海和北黄海9个站位浮标的海面10 m气压和风速观测资料对ERA5再分析资料的适用性进行了初步评估。结果表明：海面气压和风速再分析资料与观测资料具有良好的相关性,不同时间尺度的统计结果具有一定差异,累年逐月的相关性优于日均和日极值,极端天气下的相关系数最低。不同时间尺度的统计结果显示,气压再分析资料与观测值的偏差总体为负值,即高压再分析资料较观测值偏弱、低压再分析资料较观测值偏强,二者存在一定的系统性偏差;风速统计结果显示,偏差与风力级别有关,大风速时,风速再分析资料普遍小于观测值。累年逐月再分析资料反映了研究区气压和风速的季节变化特征,偏差也呈现出季节性变化,且冬季的适用性优于夏季;极端天气情况下,气压和风速再分析资料的适用性较差,需要开展进一步的订正处理。     

基于现场实测的渤海风速特性研究

风荷载是影响海洋结构物设计和安全服役最为显著的环境因素之一。利用在役海洋平台监测系统对渤海风速场展开长期监测,获得了长期的风速信息。对极值风速进行分析,利用极值Ⅰ、Ⅱ、Ⅲ型分布对风速极值的概率密度进行拟合。基于极值Ⅰ型概率分布,获得了渤海海域重现期为5 a、10 a、30 a和50 a的最大风速值。对年最大风速的脉动风分量、湍流强度、阵风因子进行了分析。考虑高频分量的影响,利用小波变换,得到了脉动风速的近似分量和细节分量,计算了实测风速的纵向和横向的空间积分尺度。对比经验脉动风谱与实测脉动风谱,证明了Davenport风速谱能够较好地拟合渤海现场风速场。     

简化疲劳方法在渤海导管架平台中的应用

API规范推荐的简化疲劳方法在渤海湾导管架平台使用中一直存在标定的问题。根据简化疲劳原理,利用渤海湾的环境数据,推导了渤海湾允许疲劳应力的表达式,在此基础上提出了计算设计疲劳年限的概念。既解决了标定的问题,又可以利用现有设计软件直接进行计算,具有很高的实用性。     

渤海湾风浪场的数值模拟

采用SWAN模型对渤海湾在定常风和非定常风作用下的波浪场进行了模拟,并利用黄骅港附近波浪统计资料对模拟结果进行了验证。结果表明：SWAN模型较好地模拟了渤海湾在定常风和非定常风作用下风浪成长和传播过程。此外,还应用ADCIRC潮流模型,初步探讨了潮流对波浪要素的影响：(1)无流存在时,波高的成长和波周期的变化是一条光滑的曲线,但当有流加入时,由于其流速和水位在一个潮周期内随时间的变化足不均匀的,其对波浪成长产生影响,使波高和周期呈不规则变化;(2)波浪成长初期,流对波高增长的影响并不明显,但当波高增大到一定程度时,流的存在对波高的影响是很明显的。     

莱州湾、渤海湾及渤海中央盆地沉积物岩芯地球化学的初步研究

本文对莱州湾、渤海湾、渤海中央盆地的海洋底质沉积环境进行了研宄,通过对17柱沉积物岩芯样品中Fe,Al,Mn,Ti的测定和分析,论述了四元素在底质表层沉积物中及在岩芯沉积物中的含量和分布规律,用数理统计的方法分析了渤海中央盆地Fe,Al,Mn,Ti的丰度值,为渤海环境背景值及环境背景历史的研究提供了重要参数。     

渤海湾北部和西部海域表层沉积物中无机碳形态研究

采用氯化钠(NaC1)、氨水(NH3·H2O)、氢氧化钠(NaOH)、盐酸羟胺(NH2OH·HC1)溶液对渤海湾北部和西部海域表层沉积物中无机碳进行了连续浸取,并将无机碳分为5种赋存形态:交换态(NaCl相)、弱碱结合态(NH3·H2O相)、强碱结合态(NaOH相)、弱酸结合态(NH2OH·HCl相)和残渣态.同时,结...     

Reliability-Based Load and Resistance Factors Design for Offshore Jacket Platforms in the Bohai Bay: Calibration on Target Reliability Index

The target reliability index has been effectively used as the best solution to deal with the relationship between the structural safety and the optimal economy in any structural design. However, the target reliability index for off-shore jacket platforms based on different sea areas in China has never been calibrated. This paper presents an approach for its calibration, and suggests many kinds of associated load cases. The uncertainties of loads and structural resistance are mainly investigated. The target reliability index for structural components, tubular joints and piles of offshore jacket platforms are discussed respectively in detail. Finally, through the calibrated results from the offshore jacket platforms of QK18-1, JZ20-2, SZ36-1 and BZ28-1 in the Bohai Bay, it is proposed to adopt 2.8 as the target reliability index of offshore jacket platforms in the Bohai Bay for a 25-year design period. The results provide significant reference for the design of offshore jacket platforms.     

Reliability-Based Load and Resistance Factors Design for Offshore Jacket Platforms in the Bohai Bay： Calibration on Target Reliability Index

The target reliability index has been effectively used as the best solution to deal with the relationship between the structural safety and the optimal economy in any structural design.However,the target reliability index for offshore jacket platforms based on different sea areas in China has never been calibrated.This paper presents an approach for its calibration,and suggests many kinds of associated load cases.The uncertainties of loads and structural resistance are mainly investigated.The target reliability index for structural components,tubular joints and piles of offshore jacket platforms are discussed respectively in detail.Finally,through the calibrated results from the offshore jacket platforms of QK18-1,JZ20-2,SZ36-1 and BZ28-1 in the Bohai Bay,it is proposed to adopt 2.8 as the target reliability index of offshore jacket platforms in the Bohai Bay for a 25-year design period.The results provide significant reference for the design of offshore jacket platforms.     

渤海湾中化学需氧量(COD)扩散、降解过程研究

对渤海湾中水质因子化学需氧量(COD)的随流输移扩散和生物化学过程进行了研究。在对有机污染物的生化降解过程进行试验研究的基础上,建立了模拟浅水、缓坡海湾有机物(COD)迁移转化规律的水质模型,并应用实测资料结果对水质模型进行了验证。     

围填海工程对渤海湾风浪场的影响

为了深入了解围填海工程对波浪场特别是风浪场的影响,针对10 a 围填海工程对渤海湾地形岸线的改变,将 SWAN(Simulating Waves Nearshore)海浪数值模式应用到渤海湾,讨论了人类大工程对渤海湾风浪场的影响.采用欧洲气象中心每天4次的风场资料作为驱动,模拟渤海湾2000年和2010年的风浪场,着重分析岸线变化显著的3个港口工程(曹妃甸、天津港和黄骅港)附近海域的波浪要素变化.研究结果表明,工程建筑物存在后,有效波高呈减小趋势,港池和潮汐通道内的有效波高减小幅度较大.港口地理位置和海底地形也与岸线变化共同影响着港口附近海域的波浪场分布.围填海工程对波浪有效波高及周期影响的程度不大,有效波高减小值在0.2 m 以下,周期几乎不变.     

Reliability-Based Load and Resistance Factors Design for Offshore Jacket Platforms in the Bohai Bay: Calibration on Design Factors

For the fulfillment of the probability-based structural design for the offshore jacket platforms in the Bohai Bay, the design factors of loads, resistance and load combinations are much necessary to be calibrated according to the proposed target reliability index. Firstly, the limit states function for the offshore jacket platforms is introduced. Then, four approaches to calibrate the factors of load and resistance are presented and compared. Afterwards, the methods to calibrate the load combination factors are developed. Finally, the factors of load, resistance and load combination for the offshore jacket platforms in the Bohai Bay are calibrated and the corresponding design formulae are recommended. The results are proved to be rational in practice, and also illustrate that the proposed target reliability index for offshore jacket platforms in the Bohai Bay is also appropriate.