长江口拦门沙地区的泥沙运动规律   总被引：12，自引：0，他引：12  

潘定安  孙介民 《海洋与湖沼》1996,27(3):279-286

依据１９８８年７月和１２月水文观测资料，通过流，盐，沙的综合分析，认识到长江口拦门沙地区的泥沙运动有与河口其他地区不同的特点，泥沙输移在水平面上和垂直面上存在着多种循环，潮流和盐水截留大量泥沙积聚的拦门沙地区，河口在盐淡水交锋地带，除了涨，落急时段外，发现在转流时期泥沙也可能产生再悬浮，从而形成一个潮周期中出现３次或４次再悬浮的特殊规律。  相似文献   

Experimental studies on the slowly varying drift motion of a berthed container ship model     

S.K. Lee  H. Choi  S. Surendran 《Ocean Engineering》2006,33(17-18):2454-2465

The effects of free-surface waves on the floating structures are of great importance in the offshore industry. Among the six degrees of motions of a surface ship the absence of restoring forces in surge, sway and yaw led to critical situations for moored ships in the recent times. The order of forces in horizontal plane and their exciting frequencies are matters of interest. The resonance with the presence of moored chains led to many accidents in the recent past. The lines in dry conditions may not give good damping and in wet condition they may trigger the system to chaotic motions and jumps. Two different loading conditions of a container ship model are tested with waves in laboratory conditions in two different drafts. The mooring lines are chosen as per scale law and the energy under the response spectrum is determined from the plots. The results give new insights into the movement of a berthed ships subjected to waves. Response of the moored ship to different loading conditions in different water depths are discussed in this paper. The paper gives the order of energy due to first-order and slowly varying movement of a berthed container model in a towing tank.  相似文献   

Action mechanism of geotextile-reinforced cushion under breakwater on soft ground   总被引：1，自引：0，他引：1  

Yuzhen Yu  Bingyin Zhang  Jian-Min Zhang 《Ocean Engineering》2005,32(14-15):1679-1708

Various measures including material experiments, centrifuge modeling tests and FEM numerical analyses were performed to study systematically the action mechanism of the geotextile-reinforced cushion under breakwater on soft ground and the effects of the strata characterization and the reinforcement condition on the stability of the breakwater-ground system. In the aspect of controlling the deformation, the geotextile-reinforced cushion under breakwater constrains the lateral displacement of both the embankment and the ground. From the viewpoint of stress, the reinforcement suppressed the range of high stress level in the system. In general, the weaker the ground is and the greater the modulus of the geotextile is, the more effective the reinforcement is. The tensile force in the geotextile is greater in the range of the main part of the embankment.  相似文献   

Comparison of two three-dimensional hydrodynamic modeling systems for coastal tidal motion     

Q.Y. Zhang   《Ocean Engineering》2006,33(2):137-151

A comparison of two three-dimensional numerical modeling systems for tidal elevations and velocities in the coastal waters is presented. The two modeling systems are: (1) the Princeton Ocean Model (POM) and (2) the MIKE 3 flow model. The model performance results for Singapore's coastal waters show that the predicted tidal elevations from the two hydrodynamic modeling systems are almost identical and are in very good agreement with field measurement data. The simulated tidal current velocities match well with field measurement data at the selected stations, but it seems that the POM provides the slightly better simulation, compared to the MIKE 3 flow model. The depth profiles of the velocities obtained from the two modeling systems may be greatly different at some time, due to the vertical diffusion coefficient calculated from different turbulent sub-models in the two modeling systems. The POM generally predicts larger peak tidal velocities. The maximum speed differences for the model results from the two modeling systems occur in the top and differ from time to time and from location to location, reaching up to 20%.  相似文献   

软土海岸地区测量控制点标志的设立     

苏衍坤  李新国  朱绪伟  苏衍国 《海洋测绘》2007,27(3):43-47

分析了软土、湿地、滩涂地区特殊地理环境对测量控制点的影响;主要探讨了此类地区控制点标志的设计、施工。借助于建筑桩基技术和道桥施工方法,首次成功实现了某三角洲湿地滩涂地区统一布网。几年来,结合滩涂湿地测量、海岸防护和滩涂开发工程对部分控制点进行了初步检测,给出了部分检测数据。应用和检测均表明:桩基标石可较好地解决软土、湿地、滩涂地区控制点布设难题,显著提高软土海岸地区测量控制点标志的稳固性,从而延长控制网的可使用期。  相似文献   

厄尔尼诺的发生与行星运动     

施平 《热带海洋学报》1993,(3)

厄尔尼诺(El Ni(?)o)现象是海-气耦合系统异常变化的表现,其起因可能不是唯一的,行星运动对地球运动的影响可能会导致El Ni(?)o的发生。根据4个半世纪内El Ni(?)o发生的历史资料,分析其发生和行星运动的关系,得出的结论是:木星赤纬的变化和火星大冲与El Ni(?)o。的发生有显著的关系,表明这2颗行星的运动可能影响El Ni(?)o的发生。文中还根据分析结桌和El Ni(?)o混沌机制的观点,探讨了行星运动对海-气系统变化的影响机制。  相似文献   

Study on Key Technology of Using Shell Sand as Backfill for Sea Reclamation   总被引：1，自引：0，他引：1  

郦能惠瞿亦容  何文钦陈晖 《中国海洋工程》2005,19(4):647-658

1 .IntroductionEpicontinental sea or land could formfromcontinental shelf because of the decreasing sea levelduring Quaternary.There is a large-area shell sand deposit more than ten meters thick in the neriticzone of China .To use the abundant marine shell sandresource as engineering material for ocean engi-neering and port engineeringis veryimportant .Sand (Gred and Bjorn,1999) ,fine sand (Zhangetal .,2002) , mediumand coarse sand (Qiuet al .,1995) ,highly weathered stone ballast (Zhanetal…  相似文献   

贵阳地表水—地下水的硫和氯同位素组成特征及其污染物示踪意义   总被引：5，自引：0，他引：5  

郎赟超  刘丛强  Satake Hiroshi  WU Jiahong  李思亮 《地球科学进展》2008,23(2):151-159

喀斯特地表水和地下水的交换活跃,地下水系统容易受到地表污染物的污染。为了解喀斯特城市地表水—地下水系统污染特征和污染物质来源,对贵阳市地表水、地下水、雨水和城市排污污水的硫同位素和氯同位素组成变化进行了研究。贵阳市不同类型水体的δ³⁷Cl值在-4.07‰～+2.03‰之间变化,δ34SSO4值变化为-20.4‰～+20.9‰。大气输入物质和城市排污污水的δ³⁷Cl、δ³⁴S及Cl^-/SO₄^2-比值与地表水和地下水的不同,稳定硫和氯同位素的结合研究为示踪地下水污染物来源提供了有效研究手段。贵阳市地下水中的Cl^-和SO^₄2-至少有4种来源,人为活动通过城市排污和大气输入向地下水系统大量输入了硫酸盐和氯离子。   相似文献   

敦化市区地下水动态特征     

王中华  赵志云  李玉璞 《吉林地质》2008,27(3)

本文按不同地下水类型,从地下水的水位、水温、水质三个方面论述了敦化市规划区地下水的动态特征。  相似文献   

我国灌区地下水调控研究现状及其发展态势     

王明娜  向友珍 《地下水》2008,30(4):21-23

现代灌溉引水工程的发展,改善了灌区的农业用水条件,但同时改变了灌区上的自然生态环境、地质条件与水文地质条件等。分阶段总结了地下水的相关研究与应用;剖析了地下水调控的必要性与重要性;分析了地下水调控研究现状;最后通过总结给出了进一步研究的建议。  相似文献