水牛蹄型深海集矿机履齿设计及牵引性能研究     

丁聪  陈旭光  刘学麟  刘茜茜  李宗晏 《海洋工程》2024,(2):26-41

作为深海采矿系统的重要组成部分,深海集矿机的技术研究和开发一直是许多国家的难题。为了提高深海集矿机在稀软沉积物上的牵引性能,基于水牛蹄的曲面结构特征和特殊几何结构,设计了一款仿水牛蹄蹄型履齿。以该款履齿的结构参数为研究对象,通过对朗肯被动土压力理论的优化,得到了仿水牛蹄蹄型履齿的牵引力解析解,建立了对应的履齿仿生参数对履齿牵引力的影响公式。结合正交试验方法进行了不同形式履齿在沉积物上运动的单、多履齿剪切试验,将仿水牛蹄蹄型履齿与直型履齿、仿水牛蹄轮廓履齿（另一种仿生履齿）进行对比试验,并通过模型车试验验证了该款履齿的可行性。结果表明：3种履齿中,仿水牛蹄蹄型履齿提供的最大牵引力最高。研究可为进一步优化仿水牛蹄蹄型履齿结构参数和提高深海稀软底质机械的牵引性能提供参考依据。  相似文献   

山东半岛东北部海域悬浮体季节分布及控制因素   总被引：1，自引：0，他引：1  

朱颖涛  冯秀丽  朱龙海  胡日军  姜胜辉 《海洋地质与第四纪地质》2021,41(2):30-42

基于2018年山东半岛东北部海域冬、夏两季悬浮体浓度、浊度及水温和盐度调查资料,分析了研究区水体悬浮体浓度的季节性变化,探讨了其控制因素。结果表明:夏季浊度在0.2~37.8FTU之间变化,冬季浊度在1.5~100.1FTU之间变化,均表现为底高表低、东高西低的特征。夏季水温分层明显,表现为表层高、底层低的特征,盐度整体无明显变化;冬季温盐垂向上混合均匀,平面上表现为近岸低温低盐水体向远岸高温高盐水体的过渡。悬浮体浓度分布受潮流、波浪、温跃层和温盐锋面等因素影响。夏季,悬浮体垂向上受到温跃层影响,底层悬浮体难以向表层输运;平面上潮混合和波浪差异性作用阻碍了悬浮体的水平输运。冬季,强风浪促使悬浮体垂向混合剧烈,表层悬浮体浓度明显较夏季变高;平面上沿岸流和黄海暖流形成的温、盐锋面阻碍了水团间悬浮体的输运。  相似文献   

杭州湾枯季水沙若干特征分析     

葛灿  潘存鸿  张沈阳 《海洋工程》2021,39(2):70-79

根据2014年1月及2017年2月杭州湾大、小潮水沙资料,计算了流速、含沙量、单宽潮量、单宽输沙量,进而分析了潮周期断面净潮量、净输沙量和区域冲淤分布。研究发现杭州湾涨、落潮平均流速比值整体较20世纪八九十年代增大,绝大部分区域大于1.0,涨潮流相对增强,澉浦南岸和金山北岸尤为显著。含沙量平面上分布澉浦、杭州湾南岸两个高值区(大潮大于3 kg/m³,小潮大于1.3 kg/m³)以及北岸湾口至乍浦之间的低值区(大潮小于2 kg/m³,小潮小于0.9 kg/m³),随潮汛变化显著,最大含沙量浓度通常滞后于急流时刻。各测站涨、落潮量和输沙量呈现“大涨大落”和“大进大出”的特征,造成杭州湾短时间尺度内的“大冲大淤”。大潮两涨两落金山与乍浦、乍浦与澉浦之间区域净输沙量可达几千万吨,净冲淤则在几百万吨。  相似文献   

桑沟湾不同形态锰的分布、季节变化及影响因素     

刘家琦  任景玲  陈晶  房瑞雪  蒋增杰 《海洋学报》2021,43(2):16-27

利用催化动力学分光光度法和两步提取法对2011年4月（春）、8月（夏）、10月（秋）和2012年1月（冬）桑沟湾海域溶解态无机锰(DIMn)和表层沉积物中的锰的含量进行测定。结果表明,桑沟湾4个季节（春季至冬季,后同）DIMn浓度呈现出近岸高、远岸低的分布特点,其平均浓度分别为(60.5±43.1) nmol/L、(42.0±30.5) nmol/L、(23.4±11.2) nmol/L和(18.2±13.5) nmol/L,呈现出明显的季节变化,即春季最高,夏季、秋季次之,冬季最低;与相邻的俚岛湾和爱莲湾相比,桑沟湾春季、夏季DIMn的浓度较高,秋季、冬季则没有显著性差异。桑沟湾表层沉积物中总Mn在4个季节的含量分别为(861±308) mg/kg、(915±322) mg/kg、(589±108) mg/kg、(653±185) mg/kg,表层沉积物中醋酸提取态Mn在4个季节的含量分别为(500±272) mg/kg、(502±232) mg/kg、(322±81) mg/kg、(345±91) mg/kg,两者均表现出近岸高、远岸低的分布特点。醋酸提取态Mn的含量在春季、夏季要显著高于秋季、冬季。悬浮颗粒物的吸附和浮游生物的利用是影响桑沟湾DIMn浓度与分布的重要因素。桑沟湾DIMn的源主要包括河流及地下水输送、大气输送、沉积物?水界面释放;汇主要包括养殖生物的清除、向黄海的输送等。简单箱式模型收支计算结果显示,桑沟湾DIMn的源略大于汇,表明除了养殖生物的清除和向黄海的输送,桑沟湾DIMn还存在其他汇。本研究的结果为桑沟湾DIMn的生物地球化学循环的深入认识提供了基础数据。  相似文献   

野鸭山至螺头山岸段海域水沙特征及冲淤变化     

朱志恩 《海洋学研究》2004,22(1):1-10

根据浙江舟山野鸭山至螺头山岸段海域4个测点的海流观测和含沙量调查(其中1个测点)资料,含沙量用1/10000感量的电光分析天平称量测定,悬沙粒度用AT 型库尔特计数器测定,底质表层泥样用激光粒度仪测定,使用DS3水准仪(其精度标准为四等)测量岸段潮滩高程,对该岸段所在海域的泥沙与潮流特征进行了对比分析并讨论了岸滩的冲淤变化。结果表明,该海域悬沙浓度由表层往底层逐渐增高,且与流速有一定的线性关系;中潮悬沙浓度低于大潮,冬季悬沙浓度高于春、夏季;大、中潮的落潮输沙量大于涨潮,大潮涨、落潮的输沙量大于中潮涨、落潮,大潮全潮单宽净输沙量大于中潮;冬季平均悬沙粒径比夏季大,春季适中;春、夏、冬季悬沙的分选系数属分选极好;悬沙的运移路径以落潮流流向为净输沙的方向;该海域的潮流为往复流,涨潮流历时短于落潮流历时,春、夏、冬季平均落潮流速大于平均涨潮流速,最大流速为1.82m/s(夏季),平均流速为0.70m/s;历史上野鸭山至螺头山的古海湾一直缓慢淤涨,1987年以来,潮滩仍缓慢淤涨,中潮滩平均淤高值约为3cm/a,岸滩平均淤进速度约为0.38m/a。  相似文献   

沉积物粒度组分空间预测的神经网络残余kriging方法     

刘付程  杨毅  张林  魏陶荣馨  王宇涵  夏量 《海洋通报》2020,39(3):363-371

针对近海表层沉积物粒度组分空间变异的尺度差异性,提出了基于广义回归神经网络残余kriging的沉积物粒度组分空间预测方法,并以海州湾沉积物粒度数据为基础,分析了其在沉积物粒度组分空间预测和底质类型制图中的应用效果。结果表明,广义回归神经网络残余kriging方法能够获得比普通kriging方法更高的沉积物粒度组分空间预测精度,并且其底质类型的总体空间预测精度达到85%以上,相应的Kappa系数也在0.8以上,显示底质制图的预测类型与样本的实测类型具有较高的一致性。新方法对于开展定量化的沉积物粒度组分空间预测和底质类型制图具有参考价值。  相似文献   

太湖梅梁湾水土界面反硝化和厌氧氨氧化   总被引：18，自引：3，他引：15  

徐徽  张路  商景阁  代静玉  范成新 《湖泊科学》2009,21(6):775-781

运用无扰动芯样实验室内流动培养、稳定同位素示踪、同位紊气态产物测定及同位素配对技术,对太湖梅梁湾北部到南部的4个梯度样点的水土界面反硝化和厌氧氨氧化速率进行研究.结果表明,梅梁湾内及湾外开敞湖区4个样点的水土界面反硝化脱氮速率为(46.36±13.26)-(16.34±22,74)μmol/(m~2·h),厌氧氨氧化脱氮速率为(7.50±2.21)-(2.05±2.90)～mol/(m~2.b).梅梁湾北部河口区水土界面总脱氮能力明显高于梅梁湾南部及开敞湖区.通过对脱氮过程的进一步研究发现.北部脱氮过程主要以上覆水硝酸盐为底物的非耦合反硝化过程(D_w)为优势过程,而梅梁湾外开敞湖区则以沉积物硝化过程耦合控制的反硝化(D_n)为主.影响D_n、D_w在反硝化中比重的主要因素是沉积物溶氧侵蚀深度和上覆水NO_3~-.浓度的差异;梅梁湾厌氧氨氧化脱氮比例占总脱氮比例为12%-14%,湾外开敞湖区则占11%,影响其比例差异的主要因子是反硝化强度的大小及其反硝化中间产物--亚硝酸盐含量的差异.  相似文献   

Recent increase of river–floodplain suspended sediment exchange in a reach of the lower Amazon River          下载免费PDF全文

Conrado M. Rudorff  Thomas Dunne  John M. Melack 《地球表面变化过程与地形》2018,43(1):322-332

We analyzed variation of channel–floodplain suspended sediment exchange along a 140 km reach of the lower Amazon River for two decades (1995–2014). Daily sediment fluxes were determined by combining measured and estimated surface sediment concentrations with river–floodplain water exchanges computed with a two‐dimensional hydraulic model. The average annual inflow to the floodplain was 4088 ± 2017 Gg yr^?1 and the outflow was 2251 ± 471 Gg yr^?1, respectively. Prediction of average sediment accretion rate was twice the estimate from a previous study of this same reach and more than an order of magnitude lower than an estimate from an earlier regional scale study. The amount of water routed through the floodplain, which is sensitive to levee topography and increases exponentially with river discharge, was the main factor controlling the variation in total annual sediment inflow. Besides floodplain routing, the total annual sediment export depended on the increase in sediment concentration in lakes during floodplain drainage. The recent increasing amplitude of the Amazon River annual flood over two decades has caused a substantial shift in water and sediment river–floodplain exchanges. In the second decade (2005–2014), as the frequency of extreme floods increased, annual sediment inflow increased by 81% and net storage increased by 317% in relation to the previous decade (1995–2004). Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

A one‐dimensional process‐based approach to study reservoir sediment dynamics during management operations          下载免费PDF全文

Lucie Guertault  Benoit Camenen  André Paquier  Christophe Peteuil 《地球表面变化过程与地形》2018,43(2):373-386

A comprehensive understanding of the dynamics of erosion and sedimentation in reservoirs under different management conditions is required to anticipate sedimentation issues and implement effective sediment management strategies. This paper describes a unique approach combining fluvial geomorphology tools and morphodynamic modeling for analyzing the sediment dynamics of an elongated hydropower reservoir subjected to management operations: the Génissiat Reservoir on the Rhône River. Functional sub‐reaches representative of the reservoir morphodynamics were delineated by adapting natural river segmentation methods to elongated reservoirs. The segmentation revealed the link between the spatial and temporal reservoir changes and the variability of longitudinal flow conditions during reservoir management operations. An innovative modeling strategy, incorporating the reservoir segmentation into two sediment transport codes, was implemented to simulate the dynamics of erosion and sedimentation at the reach scale during historic events. One code used a bedload approach, based on the Exner equation with a transport capacity formula, and the other used a suspended load approach based on the advection–dispersion equation. This strategy provided a fair quantification of the dynamics of erosion and sedimentation at the reach scale during different management operations. This study showed that the reservoir morphodynamics is controlled by bedload transport in upper reaches, graded suspended load transport of sand in middle reaches and suspended load transport of fine sediments in lower reaches. Eventually, it allowed a better understanding of the impact of dam management on sediment dynamics. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Soil erosion in the Anthropocene: Research needs   总被引：6，自引：0，他引：6       下载免费PDF全文

Jean Poesen 《地球表面变化过程与地形》2018,43(1):64-84

Soil erosion is a geomorphological and, at the same time, a land degradation process that may cause environmental and property damage, loss of livelihoods and services as well as social and economic disruption. Erosion not only lowers soil quality on‐site, but causes also significant sediment‐related problems off‐site. Given the large number of research papers on this topic, one might therefore conclude that we know now almost everything about soil erosion and its control so that little new knowledge can be added. This conclusion can be refuted by pointing to some major research gaps. There is a need for more research attention to (1) improved understanding of both natural and anthropogenic soil erosion processes and their interactions, (2) scaling up soil erosion processes and rates in space and time, and (3) innovative techniques and strategies to prevent soil erosion or reduce erosion rates. This is illustrated with various case studies from around the world. If future research addresses these research gaps, we will (1) better understand processes and their interactions operating at a range of spatial and temporal scales, predict their rates as well as their on‐site and off‐site impacts, which is academically spoken rewarding but also crucial for better targeting erosion control measures, and (2) we will be in a better position to select the most appropriate and effective soil erosion control techniques and strategies which are highly necessary for a sustainable use of soils in the Anthropocene. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献