Stress Sharing Behavior and Its Mechanism during Consolidation Process in Composite Ground Improved by Sand Compaction Piles with Low Replacement Area Ratio     

S. -K. You  K. Oda  T. -H. Kim 《Marine Georesources & Geotechnology》2006,24(4):287-304

In order to accurately design a sand compaction pile (SCP) with low replacement area ratio, it is important to understand the mechanical interaction between the sand pile and clay ground and its mechanism during consolidation process in composite ground. In this article, therefore, a series of numerical analyses on composite ground improved by SCP with low replacement area ratio were carried out. The applicability of numerical analyses, in which an elasto-viscoplastic consolidation finite element method was applied, were confirmed by comparing the results obtained from a series of laboratory model tests with the composite ground improved by SCP. Through the results of the numerical analyses, mechanical behavior of the sand pile and clay in composite ground during consolidation is elucidated, together with a stress sharing mechanism between sand pile and clay.  相似文献   

Numerical simulation of the hydrodynamic behaviour of submerged plane nets in current     

Yu-Cheng Li  Yun-Peng Zhao  Fu-Kun Gui  Bin Teng 《Ocean Engineering》2006,33(17-18):2352-2368

The aim of this paper is to investigate the shape and tension distribution of fishing nets in current. A numerical model is developed, based on lumped mass method to simplify the net. The motion equation is set up for each lumped mass. The Runge–Kutta–Verner fifth-order and sixth-order method is used to solve these simultaneous equations, and then the displacement and tension of each lumped mass are obtained. In order to verify the validity of the numerical method, model tests have been carried out. The results by the numerical simulation agree well with the experimental data.  相似文献   

Diet of albacore Thunnus alalunga from the waters of Mauritius (western Indian Ocean) inferred from stomach contents and fatty acid analysis     

Z Dhurmeea  H Pethybridge  EV Romanov  C Appadoo  N Bodin 《African Journal of Marine Science》2020,42(2):131-140

The diet of albacore Thunnus alalunga from their spawning ground in the waters of Mauritius was investigated. The stomach contents of 249 albacore individuals, caught by industrial longliners and artisanal fishers, was analysed, and the dominant prey taxa were selected for lipid and fatty acid (FA) analysis. The FA profiles of prey were compared with those of liver tissue of spawning-capable and post-spawning female albacore, using multivariate analysis. Whereas stomach content analysis identified cephalopods and crustaceans as the dominant prey items in number, FA-profile analysis identified crustaceans and fishes as the most-frequently consumed prey of post-spawning female albacore. In contrast, the FA profiles of spawning-capable albacore and those of prey showed very low similarity. Analysis of the prey suggests that although cephalopods, crustaceans and fishes could all provide albacore with the required lipids and FAs, cephalopod prey seem to be less desirable owing to their lower energy content (i.e. low in total lipid, triacylglycerol, 16:0, 18:0 and 18:1ω9). Instead, the most beneficial food appeared to be locally available fishes, which are more energy-rich and have a higher docosahexaenoic acid/ eicosapentaenoic acid ratio. These results provide new information on the trophic ecology of albacore, promote our understanding of the importance of prey type for successful reproduction of albacore, and highlight the advantages of FA profiling to study diet.  相似文献   

Distribution characteristics of zooplankton biomass in the East China Sea     

XU Zhaoli  CHAO Min  CHEN Yaqu 《海洋学报(英文版)》2004,23(2):337-346

On the basis of the data of oceanographic survey in the East China Sea in four seasons during 1997-2000 (23°30'~33°00'N, 118°30'-128°E), the variation of total biomass and diet biomass of zooplankton and their spatial-temporal distribution and relationship with the fishing ground of Engraulis japonicus are approached and analyzed. The results show that the average biomass is 65.32 mg/m3 in four seasons, autumn (86.18 mg/m3) being greater than summer (69.18 mg/m3) greater than spring (55.67 mg/m3) greater than winter (50.33 mg/m3). The average value of diet zooplankton biomass is 40.9 mg/m3. The trends of horizontal distribution both in the total biomass and the diet biomass of zooplankton are similar. The high biomass region (250-500 mg/m3) is very limited, only accounting for 1% of the investigation area. Seasonal variation of the biomass is very remarkable in the west and north parts of East China Sea coastal waters ( 29°30'N,125°E). The horizontal distribution of diet zooplankton depends on the  相似文献   

东海西北部水团分析及与渔场的关系     

刘树勋  韩士鑫  魏永康 《中国海洋大学学报(自然科学版)》1989,(Z1)

作者用聚类分析法划分浅海水团,目的在于克服大洋水团分析法进行分析所遇到的一些困难,它在根据不同海区特点确定临界值与检验值时有较大的灵活性。本文讨论了浅海变性水团与中心渔场的关系。结果表明,东海底层冷水、东海表层水和大陆沿岸水对渔业生产有重要影响。  相似文献   

南黄海鳀鱼(Engraulis japonicus)产卵场小型桡足类的数量分布     

左涛  王荣  高尚武  王克 《海洋与湖沼》2006,37(4):330-336

2000—2002年6月在黄海西南侧、山东半岛南部鳀鱼产卵场专项调查中,由底至表垂直拖网获得浮游生物中网(网孔径160μm)浮游动物样品,作者就该产卵场内四种主要小型桡足类(体长<1mm)双刺纺锤水蚤、小拟哲水蚤、拟长腹剑水蚤和近缘大眼剑水蚤的数量分布进行分析。在连续三年的6月,测区内均以小拟哲水蚤和拟长腹剑水蚤数量最多。四种小型桡足类的数量空间分布虽有一定的种间、年间差异,但总体上来说,四种小型桡足类的密集中心大多分布于山东半岛沿岸或近苏北浅滩沿岸水域。相关性分析表明,双刺纺锤水蚤和近缘大眼剑水蚤与底层水温呈正相关,与盐度呈负相关,拟长腹剑水蚤与底层水温呈负相关,与盐度呈正相关。小拟哲水蚤与温度的相关性较大。双刺纺锤水蚤和小拟哲水蚤与鳀鱼仔、稚鱼的数量分布有着较为显著的正相关。  相似文献   

浙江渔场的渔业资源动态与监测          下载免费PDF全文

宋海棠  丁天明 《海洋开发与管理》1994,11(3):27-31

本文根据历史资料和１９９３年资源动态监资料，阐明了浙江渔场及邻近海域渔业资源的变化状况，重点叙述了鲐、Ｃｈａｎ鱼、虾类、头足类的资源开发利用动态，讨论了渔业资源动态监测工作，提出今后搞好资源监测工作的建议。  相似文献   

东白令海的刺黄盖鲽渔场海洋学与渔业生物学特征     

宋云升  陈大刚 《海洋科学》1989,13(1):45-48

本文概述了东白令海形成刺黄盖鲽渔场的海洋学特征,并结合现场调查的标样侧重分析了刺黄盖鲽的渔业生物学特征,本文还概略地讨论了该鱼与渔业资源的关系。  相似文献   

Relationships between benthic macrofauna and habitat suitability for juvenile common sole (Solea solea, L.) in the Vilaine estuary (Bay of Biscay, France) nursery ground     

D. Nicolas  F. Le Loc'h  Y. Dsaunay  D. Hamon  A. Blanchet  O. Le Pape 《Estuarine, Coastal and Shelf Science》2007,73(3-4):639-650

  相似文献   

波浪经过网衣的特性研究   总被引：1，自引：0，他引：1       下载免费PDF全文

宋伟华  梁振林  黄六一  吕永林  陈伯海 《海洋与湖沼》2007,38(1):15-21

依据波浪理论,分析了波浪经过网衣后的流体特性和边界条件,研究了网衣的波浪水动力、波浪透射系数与网衣尺度、特征参数、波浪参数等的关系。设计预加张力放射系泊法进行网衣构件水槽波浪试验。试验构件由10种PE网衣和HDPE框架装配而成,试验工况是规则波,周期为0·8—2·0s,波高为50—250mm。结果表明,作用在网衣上的水平波浪力变化规律与波浪基本一致,呈现周期性和不对称性变化;波浪力变化曲线呈现司托克斯二阶波形状,波峰较陡,波谷较平坦,和波面图相似;网衣水平波浪力周期峰值大约与波高的2·6次方、波长的0·8次方成比例,与网衣宽度l线性相关;随着特征参数d/a增大,网衣波浪力呈线性增加变化,透射系数减少,网衣消浪能力主要集中在网衣水表层。同时设计多层网衣组合的柔性浮式防波堤波浪试验,其消浪能力除了与网衣尺寸、特征参数等相关以外,还与网衣间隔距离有一定的关系。水槽试验时波浪最小透射系数下降到71%左右,从经济、实用角度表明,可用网衣来制作能防护渔业设施的柔性浮式防波堤。  相似文献