沐官岛水库蓄水初期盐分运移数值模拟     

赵全升  鲁静  邵争平  高增文  冯娟 《水文地质工程地质》2008,35(4):6-10

沐官岛水库是一个拟建的河口海湾水库,库底为富含咸水的潮滩沉积物。这一特殊的地质及水环境条件直接关系到水库未来的水质安全和正常的调度运行,所以必须准确地确定水库水体中盐分空间分布这一关键问题。本文依据现场调查、钻探及室内实验资料,通过垂直方向线性插值技术,建立了沐官岛水库蓄水初期盐分运移准三维模型,模拟了水库蓄水初期在内源盐分释放影响下,库水盐分的演化过程。结果表明:若遇平水年开始蓄水,当蓄水至1.5m时,该层含盐量在平面上的变化范围主要在0.30~1.30g/L之间;当蓄水至4.5m时,该层含盐量在平面上的变化范围主要在0.30~1.55g/L。  相似文献   

高速铁路路基黄土滑移变形的动力数值模拟     

王家鼎  谷天峰  任权 《水文地质工程地质》2008,35(5):19-23

以郑(州)-西(安)高速铁路为例,选择典型路段(华阴、潼关、灵宝和偃师等),采集大量原状黄土样品,进行动三轴试验,获得一系列黄土动力学参数,如动弹模、动阻尼、残余应变等,进而建立高速铁路黄土路基动力学数值模型。按该线路地震危险性分析结果,合成8条人工地震波(50年10%和2%的超越概率水平),输入该动力学模型中进行计算。结果表明:黄土路基的横向和纵向变形都随着地震力的增大而增大,从而导致黄土滑移和震陷,这与现场激振试验及动三轴震陷试验结果基本一致。该结果为郑西高速铁路抗震陷和抗滑移设计提供了重要依据,并提出了切实可行的黄土抗震陷和滑移地基处理措施,已应用于该高速铁路的设计与施工中。  相似文献   

新疆叶尔羌河流域地下水同位素特征及其补给来源分析   总被引：3，自引：2，他引：1       下载免费PDF全文

武倩倩  任加国许 模 《中国地质》2008,35(2):331-336

笔者以新疆叶尔羌河流域为例,在研究区水文地质调查的基础上,根据不同区域、不同深度D、~(18)O和T值的变化分析地下水补给来源.解决了传统研究方法很难解决的问题.为干旱地区地下水起源及空间分布规律研究提供了新思路。研究结果表明:(1)研究区地下水不是来自大气降水的直接入渗,而是地表水渗漏补给。(2)流域分为两个独立的地下水循环系统,分别接受叶尔羌河与提孜那甫河河水补给。(3)潜水和承压水的起源相同,属统一的地下水系统。(4)地下水径流表现为倾斜平原区径流强烈,地下水以水平运动为主;细土平原区地下水径流迟缓,地下水以垂直蒸发运动为主.径流方向与地表水流向密切相关。  相似文献   

青藏高原西北缘祁漫塔格山中新世快速抬升的磷灰石裂变径迹证据   总被引：2，自引：0，他引：2  

拜永山  任二峰  范桂兰  许长青 《中国区域地质》2008,(7):1044-1048

对祁漫塔格山体不同海拔高度所取的9个磷灰石样品的裂变径迹分析结果表明,东昆仑西段中新世早中期为主要的隆升期且隆升速率较高,早期隆升速率为111m／Ma,晚期隆升速率为98m／Ma,总体隆升速率为100m／Ma。样品显示出磷灰石裂变径迹长度大致分2类,一类磷灰石裂变径迹长度为（12．21±10．20）-（13．75±0．30）μm,径迹长度分布图基本上为窄而对称的正态分布,反映具有快的剥露冷却速率,未受到后期热事件的干扰。另一类磷灰石裂变径迹长度为（11．88±0．33）～（13．32±0．27）μm,较前一类具有稍慢的剥露冷却速率,并且受到了后期热事件的干扰。  相似文献   

冲绳海槽北部稀土元素沉积地球化学研究   总被引：4，自引：1，他引：4  

翟世奎  陈志华 《海洋地质与第四纪地质》1996,16(2):47-56

本文对冲绳海槽北部海底表层沉积物和４个柱将苦芯沉积物样品的稀土元素沉积地球化学特征进行了系统的分析。研究结果表明：调查区表层沉积物ＲＥＥ的分布主要与沉积物的物质组成有关，特别是海洋生物沉积物组份的比例不仅影响ＲＥＥ总量的分布，而且影响标准化ＲＥＥ分布模式的形态。  相似文献   

A Forced System of Two Cylinders with Various Spacings   总被引：3，自引：0，他引：3  

邹建锋  任安禄邓见 《中国海洋工程》2004,18(3):391-402

The spectrum characteristics and wake structures for a circular cylinder oscillating in a wake are investigated by use of the currently modified virtual boundary method. A forced system of two cylinders with a small spacing ( the downstream one is made to oscillate in the transverse direction) is studied and interesting flow characteristics are observed. A vortex switch and the change of vortex modes (between 2S mode and 2P mode) are observed in the “lock-in“ region. Vortex bands are formed and lost with the increasing excitation frequency. Information concerning saddle points in the flow field is obtained for different excitation frequencies. For a forced system of two cylinders with a large spacing, the upstream cylinder sheds vortexes because there is no downstream cylinder oscillating in the wake. No distinct “lock-in“ response is found for the downstream cylinder.  相似文献   

远区台风“三巴”对长江口波浪动力场的作用机制     

任剑波  何青  沈健  徐凡  郭磊城  谢卫明  朱磊 《海洋科学》2020,44(5):12-23

针对远区台风对河口波浪动力场的影响问题,利用第三代波浪模式SWAN计算了远区台风"三巴"期间长江口波浪动力场分布,分析了陆架至河口区的波浪能量耗散和波致泥沙侵蚀的时空分布,发现波浪由外海向近岸传播过程中,波-波相互作用导致能量由高频向低频转换,周期和波长逐渐增大,近底层轨道流速增大,能量密度增高;阐明白帽破碎是维持深水区波浪能量平衡和限制波高成长的主要机制,底摩擦耗能和水深诱导的破碎耗能是长江口横沙东滩和崇明东滩邻近海域波高衰减的主要原因;提出波浪产生的底部切应力与相对水深有关,当波浪传播到浅水区时,波长和周期越大,波浪切应力越大。研究揭示了与河口相距数百公里的远区台风能够对长江口波浪动力场产生明显影响,河口水下三角洲前缘是最容易受到波浪侵蚀的区域,研究成果弥补了目前关于陆架远区台风对河口波浪动力场影响研究的不足,对深化认识远区台风对长江口动力环境、地貌演变、航运安全和滩涂保护等有重要科学意义。  相似文献   

The European vision for oceans and seas—Social and political dimensions of the Green Paper on Maritime Policy for the EU     

Juan Luis Suárez de Vivero 《Marine Policy》2007

The EU Green Paper on Maritime Policy is the European response to the new generation of ocean strategies based on science, technology and innovation aimed at new objectives, such as the strengthening of security and access to new resources. The European character of the proposal is found in the presence of social, cultural and historical elements, what is called the “European vision”. The viability of a European vision of the oceans and the idea of maritime empire as an extension of the current concept of empire within the general context of emerging ocean strategies are the elements offered up for debate on this European Union initiative.  相似文献   

Impact of Two "El Niño" Events of Different Intensity on the Hypoxic Soft Bottom Macrobenthos off the Central Peruvian wast     

Juan  Tarazona  Wolf E.  Arntz Elba  Canahuire 《Marine Ecology》1996,17(1-3):425-446

Abstract. Monthly changes in the community structure of hypoxic soft-bottom macrobenthos have been studied at a station at 34 m depth in Ancón Bay (Peru) before and during two El Niño (EN) events. Of these events, 1982-83 is considered the strongest, and 1991–93 one of the most prolonged in the 20th century. On the oceanographic scale, EN 1982–83 ranges as "very strong", whereas EN 1991–93 ranges as "moderate".
The thermal anomalies at the station during EN 1982–83 (+ 7.8 °C) were almost twice those of EN 1991–93 (+ 4.1 °C). However, the community changes were not in all cases proportional to the extent of warming. Species numbers increased in a similar way (up to 24 species from near zero in each of the two events), but maximum faunal density was five times higher, and mean biomass was twice as high in 1982–83 compared with the event a decade later. Species diversity was slightly higher during EN 1982–83, whereas successional and trophic changes occurred on a broader scale during EN 1991–93. On the whole, the impact of the long-lasting event on the small soft-bottom macrofauna was not much weaker than that of the exceptionally strong event.
The authors discuss the mechanisms which may be responsible for the differences and similarities encountered in the benthic community dynamics during these two events. Both in the unusually strong and the unusually long EN, the community revealed a pattern of early biological response several months ahead of the onset of local warming which marks the official begin of EN. The question is addressed to what extent the increase of certain parameters in the benthic community could be used for predictive purposes.  相似文献   

Determination of technical efficiency of fisheries by stochastic frontier models: a case on the Gulf of Cadiz (Spain)     

Garcia del Hoyo  Juan Jose; Castilla Espino  David; Jimenez Toribio  Ramon 《ICES Journal of Marine Science》2004,61(3):416-421

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