Suction force below plate anchors in soft clay

The results of a number of laboratory model tests for the short‐term ultimate uplift capacity of a circular plate anchor embedded in saturated soft kaolinite and montmorillonite are presented. The tests were conducted with and without venting the bottom of the plate anchor in order to determine the variation of the suction force with embedment ratio. The variation of the suction force is presented in terms of the undrained shear strength of the clay and also the net ultimate uplift capacity.     

威海沿岸海域潮汐特征分析

文章主要选取国家海洋局成山头海洋环境监测站1996—2016年的潮位、潮差月值资料,利用线性回归法,对威海沿岸海域近21年来的潮汐特征进行分析。结果表明:威海沿岸海域近21年的平均潮位、最高潮位、最低潮位、平均潮差、最大潮差整体上均呈上升的变化趋势,但气候倾向率各不相同,分别是2.57cm/(10a)、5.872cm/(10a)、4.137cm/(10a)、1.017cm/(10a)、2.604cm/(10a)。     

基于五种油源的中重度风化溢油的常规鉴定指标的应用效果评估

本文利用采集于我国三大油田的五种原油样品开展了长达210天的溢油风化模拟实验,并依据相对偏差和重复性限数学分析法,进行溢油风化过程分析和诊断比值应用效果评估。研究结果表明:经过210天的风化,溢油鉴定诊断比值发生明显改变;其中来源于萜烷、甾烷和多环芳烃的诊断比值变化率要远低于正构烷烃,可用于中长期风化溢油鉴定。此外,研究发现,在这些有效诊断比值中有4个变化率较小,相对偏差低于5%,保持了较好的稳定性,更适合于重度风化溢油鉴定。     

岬湾海滩剖面中长期变化特征及其控制因素——以青岛石老人海滩为例

了解海滩剖面变化可以更好地理解海滩动态过程。利用2007年5月~2014年12月近8 a青岛石老人海滩剖面的实测资料,计算剖面各段单宽体积变化量及后滨宽度,结合交叉小波和小波相干分析方法,探讨海滩剖面中长期淤蚀变化特征及其控制因素。结果表明,近8 a来海滩剖面表现为侵蚀状态,不同岸段侵蚀程度不同。剖面1岸段侵蚀明显,剖面2和剖面3岸段轻微侵蚀。剖面的变化过程可划分为平稳期、剧变期和微调期3个时期。各时期剖面的季节性变化较复杂,平稳期具冬蚀夏淤的交替变化特征,整体淤蚀量较小;剧变期剖面呈阶段性蚀退,变化幅度相对较大,微调期剖面可能仍处于剧变期的恢复阶段,季节性变化不明显。剧变期和微调期的小波交叉谱和相干谱分析显示,波浪和前滨单宽体积相干性较好,尤其当大于2 m的波高达到10%以上,海滩地形可以和波高变化产生同周期的变化。因此波高变化基本控制了剖面的季节变化。而海滩长周期变化主要受控于风暴潮作用及其漫长的恢复期,沿岸输沙和海平面变化则一定程度上导致了剖面长期侵蚀格局的形成。     

Distributional characteristics of grain sizes of surface sediments in the Zhujiang River Estuary

Distributions of the parameters of sedimentary grain sizes and their correlations were studied to trace the sources of silts and their movement trends in the Zhujiang River Estuary based on the analyses of grain sizes from more than 1080 sedimentary samples. The distributions of the median diameter, public value, quartile deviation, and skewness of sediments were complex in the Zhuiiang River Estuary mainly because of the impact of the matter source regions, distances from the source regions, and hydrodynamic conditions, such as waves, tidal currents, and coastal currents. Analyses of the parameters of the grain sizes for the various types of sediments showed that the distributions of the surface sediments in the Zhujiang River Estuary were controlled by many factors. Their matter sources were mainly the sediments discharged from the runoffs and ebb tidal currents, and from the open sea. The sediments mainly moved by suspension movement. The silts formed a large area of sediments with suspended fine silts in the Zhujiang River Estuary by internal adjustment transportation in the area, and moved toward the western coast of the Zhujiang River Estuary under the effect of Coriolis forces and coastal currents.     

海洋环境移动平台观测技术发展趋势分析

文中论述了海洋环境移动平台观测技术发展现状,强调移动平台观测技术的重要性。通过剖析移动平台观测技术谱系,从顶层设计、关键技术创新、平台载体系统集成及应用技术等方面,分析了未来技术发展趋势,提出了加强我国海洋环境移动平台观测技术的发展建议。     

东海沿岸海水表层温度的变化特征及变化趋势

根据东海沿岸引水船、嵊山、大陈、南麂、北礵、平潭、厦门和东山8个海洋观测站的40a表层海水温度(SST)资料进行了统计与分析.研究结果表明:东海沿岸SST主要受制于太阳辐射,呈南高北低分布,但也不同程度地受到当地地理环境、气候环境、水文环境的影响;SST的年变化具有显著的年周期和半年周期;东海沿岸SST存在多种显著周期的振荡,且南北测站SST的主导振荡有差异;就近40a的资料而言,东海沿岸的SST总体呈上升趋势,其中冬季上升幅度最大,暖冬是SST总体呈上升趋势的重要因素.     

吉林省敦化市乡村人群气候变化感知的偏差及群体分异研究

通过问卷调查,具体分析了吉林省敦化市乡村人群对气候变化趋势和极端冷暖年的感知偏差及人群分异.发现乡村人群对气候变化趋势的感知与科学事实比较符合,由于对变暖转折年代更敏感,因而对变暖的确认度在一些时段与科学事实在变化程度或幅度上存在比较大的偏差.乡村人群对极端冷暖年不如对趋势感知的准确度高.经验积累影响乡村人群对气候变化...     

新疆北天山中长期地震活动形势分析

在收集全天山尽可能完整的地震目录资料和进行较为科学的天山地震活动分区的基础上，按照从大区到小区、从整体到局部的层次性分析思路，分析了新疆北天山地震活动的阶段性及关联性特征，并进行了b值外推和应变能累积预测分析，估计了新疆北天山强震发生的累积概率和马尔柯夫概率，从而对新疆北天山未来3－10年的中长期地震活动形势提出了分析预测意见。     

A Nonlinear Model of Surf Beat

A nonlinear short-wave-averaged (surf beat) model is presented. The model is based on that of Roelvink (1993), but the numerical techniques used in the solution are based on the so-called weighted-averaged flux (WAF) method (eg Watson et al., 1992), with time-operator splitting used for the treatment of some of the source terms. This method allows a small number of computational points to be used, and is particularly efficient in modelling breaking long waves. The short-wave (or primary-wave) energy equation is solved using a more traditional Lax-Wendroff technique. Results of validation indicate that the model performs satisfactorily in most respects.