动荷载作用下海底粉土的孔压响应及其动强度   总被引：5，自引：0，他引：5  

冯秀丽  叶银灿  马艳霞  林霖 《中国海洋大学学报(自然科学版)》2002,32(3):429-433

本文选用近海分布较广的粉土为研究对象 ,利用室内动三轴试验结果 ,找出动荷载作用下粉土的动应力应变关系 ,分析模拟波浪荷载作用下粉土中的孔压响应、临界循环次数 ,确定波浪作用下粉土的应力状态、破坏临界循环次数 ,判断不同深度处的粉土发生液化的可能性及发生液化所需要的时间 ;研究粉土在动荷载作用下的强度降低 ,为海上工程设计和施工提供科学依据。  相似文献   

新世纪大洋钻探"三角鼎立"中的欧洲联合体     

刘玉柱  高月华 《海洋地质前沿》2002,18(5):19-20

欧洲为了与美国、日本在IODP中处于同等重要的地位，成立了由ODP成员参加的欧洲大洋钻探科学指导委员会（ESCOD）和JEODI组织，并开展了IODP之前的一系列准备活动。在其中的APLACON会议上，论证了IODP中第三类特定钻探平台的必要性，讨论了该类平台在某些研究范围内的重要作用，包括研究地球历史中的极端气候（北极海区）、重建白垩纪－第三纪的水文地理学、气候的快速变化、沉积盆地形成与过程以及固体地球过程等。  相似文献   

A semi-analytical solution for random wave-induced soil response and seabed liquefaction in marine sediments     

Haijiang Liu  Dong-Sheng Jeng   《Ocean Engineering》2007,34(8-9):1211-1224

In this study, unlike most previous investigations for wave-induced soil response, a simple semi-analytical model for the random wave-induced soil response is established for an unsaturated seabed of finite thickness. Two different wave spectra, the B-M and JONSWAP spectra, are considered in the new model. The influence of random wave loading on the soil response is investigated by comparing with the corresponding representative regular wave results through a parametric study, which includes the effect of the degree of saturation, soil permeability, wave height, wave period and seabed thickness. The maximum liquefaction depth under the random waves is also examined. The difference on the soil response under the two random wave types, B-M and JONSWAP frequency spectra, is also discussed in the present work.  相似文献   

考虑多种非线性因素的张力腿平台动力响应   总被引：1，自引：1，他引：1  

曾晓辉  沈晓鹏  刘洋  吴应湘 《海洋工程》2006,24(2):82-88

建立了一种考虑多种非线性因素的张力腿平台(TLP)分析模型,其中包括六自由度有限位移,各自由度之间的耦合,瞬时湿表面,瞬时位置,自由表面效应及粘性力等因素引起的非线性。推导出TLP六自由度非线性运动方程。对某典型张力腿平台ISSC TLP进行了时域上的数值计算,求得该平台在规则波作用下的六自由度运动响应。用退化到线性范围的解与已有解进行了对比,吻合良好。数值结果表明,综合考虑非线性因素后响应明显改变,建议在设计TLP平台的时候,考虑非线性因素的影响。  相似文献   

Subsurface Water Masses in the Central North Pacific Transition Region: The Repeat Section along the 18° Meridian     

Toshio Suga  Kazunori Motoki  Kimio Hanawa 《Journal of Oceanography》2003,59(4):435-444

A repeat hydrographic section has been maintained over two decades along the 180° meridian across the subarctic-subtropical transition region. The section is naturally divided into at least three distinct zones. In the Subarctic Zone north of 46°N, the permanent halocline dominates the density stratification, supporting a subsurface temperature minimum (STM). The Subarctic Frontal Zone (SFZ) between 42°–46°N is the region where the subarctic halocline outcrops. To the south is the Subtropical Zone, where the permanent thermocline dominates the density stratification, containing a pycnostad of North Pacific Central Mode Water (CMW). The STM water colder than 4°C in the Subarctic Zone is originated in the winter mixed layer of the Bering Sea. The temporal variation of its core temperature lags 12–16 months behind the variations of both the winter sea surface temperature (SST) and the summer STM temperature in the Bering Sea, suggesting that the thermal anomalies imposed on the STM water by wintertime air-sea interaction in the Bering Sea spread over the western subarctic gyre, reaching the 180° meridian within a year or so. The CMW in this section originates in the winter mixed layer near the northern edge of the Subtropical Zone between 160°E and 180°. The CMW properties changed abruptly from 1988 to 1989; its temperature and salinity increased and its potential density decreased. It is argued that these changes were caused by the climate regime shift in 1988/1989 characterized by weakening of the Aleutian Low and the westerlies and increase in the SST in the subarctic-subtropical transition region. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

The emerging role of climate in post-smolt growth of Atlantic salmon   总被引：1，自引：1，他引：1  

Friedland  Kevin D.; Chaput  Gerald; MacLean  Julian C. 《ICES Journal of Marine Science》2005,62(7):1338-1349

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Storminess and vulnerability along the Atlantic coastlines of Europe: analysis of storm records and of a greenhouse gases induced climate scenario     

I. Lozano  R. J. N. Devoy  W. May  U. Andersen 《Marine Geology》2004,210(1-4):205-225

Identification of the distinctive circulation patterns of storminess on the Atlantic margin of Europe forms the main objective of this study; dealing with storm frequency, intensity and tracking. The climatology of the extratropical cyclones that affect this region has been examined for the period 1940–1998. Coastal meteorological data from Ireland to Spain have been linked to the cyclone history for the North Atlantic in the analysis of storm records for European coasts. The study examines the evolution in the occurrence of storms since the 1940s and also their relationship with the North Atlantic Oscillation (NAO). Results indicate a seasonal shift in the wind climate, with regionally more severe winters and calmer summers established. This pattern appears to be linked to a northward displacement in the main North Atlantic cyclone track.

An experiment with the ECHAM4 A-GCM at high resolution (T106) has also been used to model the effect of a greenhouse gases induced warming climate on the climatology of coastal storms in the region. The experiment consists of (1), a 30-year control time-slice representing present-day equivalent CO₂ concentrations and (2), a 30-year perturbed period corresponding to a time when the radiative forcing has doubled in terms of equivalent CO₂ concentrations. The boundary conditions have been obtained from an atmosphere-ocean coupled OA-GCM simulation at low horizontal resolution. An algorithm was developed to allow the identification of individual cyclone movements in selected coastal zones. For most of the northern part of the study region, covering Ireland and Scotland, results describe the establishment by ca. 2060 of a tendency for fewer but more intense storms.

The impacts of these changes in storminess for the vulnerability of European Atlantic coasts are considered. For low-lying, exposed and ‘soft’ sedimentary coasts, as in Ireland, these changes in storminess are likely to result in significant localised increases in coastal erosion.  相似文献   

东海围垦滩地强夯作用下孔隙水压力响应试验研究     

霍素霞  刘涛  高振会 《海岸工程》2006,25(1):41-46

围垦滩地饱和粉土地基属于软土地基的一种,其含水量高,渗透性差,强夯加固作用使地基土中的孔隙水压力瞬时升高,且短时间内得不到消散,容易出现“橡皮土”。通过现场试验研究了饱和粉土地基在强夯作用下孔隙水压力的响应规律,确定了两遍强夯之间的间歇时间和强夯的影响深度,以便优化强夯参数,正确指导强夯施工。  相似文献   

半潜式超大浮体连接器动力特性的一种时间序列分析方法   总被引：1，自引：2，他引：1  

王璞  余澜 《海洋工程》2002,20(3):9-13

根据刚性模块弹性连接器 (RMFC)假设研究由 3个模块连接而成的半潜式超大浮体MobileOffshoreBase(MOB)的波浪载荷动力响应。模块和连接器动力响应根据时间序列法计算 ,这种方法包括海况模拟 ,波浪载荷计算和结构响应计算三个主要部分。通过对结构的适当简化 ,根据Airy波理论 ,Morrison公式以及流体中的结构运动方程、弹性连接器变形方程 ,计算求得MOB在不规则海况下的动力响应 ,并将其与相关文献中的结果进行比较 ,表明该方法有良好的精确性  相似文献   

Hydroelastic Analysis of Very Large Floating Structures Using Plate Green Functions   总被引：4，自引：0，他引：4  

闫红梅  崔维成  刘应中 《中国海洋工程》2003,17(2)

1 .IntroductionRecentlygreatinteresthasbeenshowninthedevelopmentofverylargefloatingstructuressuchasMegaFloatofJapan (Isobe ,1 999)andMOBofUSA (Remmers ,1 999) .Owingtotheirextremelargesizeandgreatflexibility ,thecouplingbetweenthestructuraldeformationandfluidmotionissignifi cant.Thisisatypicalproblemofhydroelasticity .Efficientandaccurateestimationofthehydroelasticresponseofverylargefloatingstructuresinwavesisveryimportantfordesign .Manymethodshavebeenproposedinliteratureforthepredictiono…  相似文献