马里亚纳海沟“挑战者深渊”营养盐的垂直分布特征

2015年12月在马里亚纳海沟"挑战者深渊"进行了定点样品采集,对温度、盐度、溶解氧、pH等环境参数进行了分析,讨论了营养盐的垂直分布特征、各形态营养盐结构特征及影响因素。研究发现,溶解氧在表层具有最大值,在1000 m左右出现极小值,而在8700 m深度具有较高溶解氧值(5.79 mg·L^-1),这可能与富氧水团的存在有关。硝酸盐表层含量较低,在1000和5367 m处出现双峰值。在表层水体中,溶解有机氮、磷是溶解总氮、溶解总磷的主要存在形式,表层以深,溶解无机氮、磷逐渐占据主导地位。磷酸盐表层含量最低,在1000 m处达到最大值,之后随着深度的增加浓度逐渐降低;硅酸盐在表层含量较低,在约4000 m处有最大值161.65μmol·L^-1,在4000 m以深,硅酸盐仍维持较高浓度。结果表明马里亚纳海沟"挑战者深渊"的溶解氧、pH及营养盐的垂直分布特征与大洋环流、海沟形态以及生物活动密切相关。     

底部透空不透水建筑物波压力研究

底部透空不透水建筑物是近海工程中的一种新型结构,与传统水工建筑物相比,其能灵活适应基床不发生变形、阻止波浪进入后方造成破坏。本文通过构建物理模型,在波浪水槽中进行试验,测试了底部透空不透水直立建筑物不规则波作用,得到了不同水深、相同波浪要素时,该型直立建筑物迎浪面和底面的水平总力最大时各测点正向波压力和负向波压力数据。对比分析了不同水深下底部透空不透水直立建筑物的水平总力及垂直力,总结了波峰和波谷作用下波浪力沿建筑物表面的分布规律,可为海岸工程结构设计提供依据。     

Evaluation of Inner Soil Pressure Acting on Opened Bottom Cylindrical Structure

1 .IntroductionAnopenedbottomcylinderisathinshellstructureplacedonarubblebaseorembeddedinasoilfoundation .Itiswidelyusedintheconstructionofwharves ,breakwatersandotheroceanprojects.Thestructureisusuallyfilledwithgranularmaterialstoensurethestabilityofthestructurealongwiththeweightofthecylinder.Hence ,itisconsideredasagravitytypeofstructure .However,thesettlementofthecylinderisdifferentfromthatofthetraditionalgravitytypeofstructureandsodoesthedistribu tionofinnersoilpressureovertheopenedbottom…     

Simplified Method for Calculating Standing Wave Pressure on Vertical Breakwater

Through numerical modeling, a kind of simplified calculating method for standing wave pressure on vertical face breakwater have been put forward. Not only the formulas proposed in this paper are simple in form and very easy in use, but also they possess continuity on the full range of standing wave. And more, the precision requiremennts of calculation can be satisfied to a certain extent in engineering practice.     

直立式防波堤兼码头水工结构设计与试验研究

基于青岛崂山前海直立式防波堤兼码头工程的设计,通过规范计算值与断面物理模型试验数据的对比分析,合理确定断面尺度、堤顶高程和越浪量等重要设计参数。特别是通过多组试验的数据分析,对挡浪墙的外形尺度和护底宽度进行优化,采用通过增大护底块体重量的方式有效地减小护底长度,充分运用试验手段对于设计规范的护底相关规定做出了有益的探索和补充,为深水直立式防波堤的设计改进提供了借鉴。     

黄海水温垂直剖面的遥感反演与数值预报模型

基于黄海水温垂直剖面分层结构统计分析,建立了一个卫星遥感SST反演水温垂直剖面的参数化模式,以该模式反演数据作为一维数值预报模式的初值,同时用大气预报场资料作为预报模式的过程资料,发展了一个以卫星遥感资料作为主要输入量的黄海水温垂直剖面的数值预报模型.模型实现了利用卫星遥感资料反演预报黄海水温垂直剖面的目的,5 d时效的预报效果明显优于已往强温跃层数值预报模式.     

Evaluation of Excess Pore Water Pressure Characteristics in Sand Mat Used for Recycling Dredged Soil

The design of sand mats should be reviewed on the basis of excess pore pressure behavior, which can be obtained by combining the characteristics of soft ground with the permeability of the mats. In this study, a banking model test was performed using dredged sand as the mat material to investigate the hydraulic gradient distribution of sand mats. The results were compared with numerical analysis results utilizing Terzaghi's one-dimensional consolidation equation. The results showed that the pore pressure was influenced by an increase in the amount of settlement at the central part of the sand mat as the height of the embankment increased. The measured decrease of the pressure head due to the residing water pressure in the sand mat was delayed compared to the numerical analysis results. Accordingly, sand mats should be laid to reduce the increased hydraulic gradient at the central part of the embankment.     

Role of Vertical Resolution in Numerical Models Towards the Intensification,Structure and Track of Tropical Cyclones

The impact of vertical resolution on the evolution and movement of tropical cyclones was studied using NCAR MM5 model with a horizontal resolution of 9 km. Four numerical experiments were performed with different vertical resolutions, that is, with 23 vertical levels as control experiment, and 36 vertical levels with high resolution in the lower troposphere, 33 vertical levels with high resolution in the upper troposphere and 46 vertical levels with increased vertical resolution throughout the troposphere as relative to base experiment. The results indicate that increased vertical resolution in the lower troposphere produces efficient intensification and better structure in terms of eye and eyewall. Increased vertical resolution at lower levels improves the prediction of vertical shear of horizontal wind. Experiments with high resolution in the lower troposphere and high resolution throughout the troposphere simulate better track up to 72 hours.     

竖直螺旋槽管强化传热传质特性的研究—壁面几何形状对液膜流动特性的影响

该文研究竖直螺旋槽管壁面液膜形成及流动特性。建立了单组分流体的物理和数学模型并得出解析解 ,并分析了壁面几何形状对液膜流动特性的影响。结果表明 :液膜的形状主要受表面张力影响 ,在表面内弯处液膜较厚 ,而在槽道起始部液膜较薄。相对于光滑直管 ,竖直螺旋槽管壁面液膜具有均匀的厚度分布和更好的传热传质性质。     

雅浦海沟南缘海底表层矿物碎屑粒度特征及其物源指示

对取自雅浦海沟南缘海域的112个表层沉积物样品,进行了矿物碎屑粒度特征和粒度组分分离分析,探讨了矿物碎屑的来源。结果表明,研究区海底表层沉积物的矿物碎屑主要粒级是粉砂和黏土。使用粒度组分分离方法,由细到粗共分离出四个组分：M1、M2、M3和M4,其中M1和M2为风尘物质,遍布整个研究区;M3和M4为火山碎屑和硅质生物碎屑,主要分布在雅浦海沟和西加洛林海槽附近。雅浦海沟和西加洛林海槽内矿物碎屑偏粗,峰态值偏小,分选差,反映物源复杂;西加洛林海盆内矿物碎屑偏细,峰态值偏小,分选较差,物源多样;西加洛林海脊处矿物碎屑最细,峰态值普遍较大,分选好,优势粒级明显,物源相对单一。从海脊、海盆到海槽与海沟,矿物碎屑粒径变粗,分选变差,物源逐渐变得复杂,表明矿物碎屑分布与构造环境密切相关。     

黄海、渤海底层温度数值预报方法的研究

根据文献［ｌ］建立的底层温度（ＴＨ）与其水柱垂向平均温度（）的经验关系，结合流体动力学方程和（垂向平均）热传导方程，发展了以水气温差和风速为已知量的底层温度二维数值预报模式。该模式避开了海面热量和动量输入在垂直水柱中分配的复杂物理过程而直接报出底层水温场，具有较好的实用性；此外，从试报结果看，效果令人满意。     

用砂泥岩互层模型检验垂向分辨率

根据实际生产经验与理论分析,瑞利准则将垂向分辨率定义为λ／4可能并不合理。为了检验垂向分辨率,首先依据一次定性分析的结论,然后在此基础上设计一系列砂泥岩互层模型实验定量地分析并得出结论：将垂向分辨率定义为λ／8更为合理。     

OWC装置空气透平压降作用试验研究

空气透平的压降作用及由其带来的空气流速变化,是串联2次能量转换过程、实现两转换过程耦合的核心要素.试验主要是在物理模型的基础上,对带有冲击式透平的OWC装置能量转换影响因素进行研究.试验主要考察2次能量转换耦合作用下,气室内自由水面变换、气室内压强变化、输气管内空气流速变换及三者耦合与相互作用.     

Physical Modeling of a Footing on Soft Soil Ground with Deep Cement Mixed Soil Columns under Vertical Loading

Deep cement mixing (DCM) technique is a deep in-situ stabilization technique by mixing cement powder or slurry with soft soils below the ground surface to improve their properties and behavior. Some of DCM treated soft soil grounds are approximately in a plane-strain condition; for example, a fill embankment on DCM improved ground. In this study, a plane-strain physical model was created with instrumentation and used to investigate the bearing capacity and failure mode of a soft soil improved by an end-bearing DCM column group. This study focuses on the observed wedge-shaped shear failure of the model ground and attempts to give an account of the failure. Two different methods are used to calculate the bearing capacity of the model ground, and the computed values are compared with the measured ones. It is found that the simple Brom's method gives a better estimate of the bearing capacity of the present model ground. It is also found that measured data of pore water pressures at different locations in the soft soil indicate coupling between failure of columns and consolidation of the soft soil. This study has presented the first time that a wedge-shaped block failure was observed for pattern of DCM treated soil ground.     

A Model Test on the Behavior of a Static Drill Rooted Nodular Pile Under Compression

A static drill rooted nodular pile is a new type of composite pile foundation with high bearing capacity, and mud emissions can be largely reduced using the static drill rooted method. This report presents a model test on the behavior of this composite pile in a test box. The load-displacement response, axial force, skin friction, and mobilized base load are discussed in the report; in particular, the force in the cemented soil was investigated based on the measured data. Moreover, the finite element software ABAQUS was used to help investigate this behavior more thoroughly. It was determined that the function of the cemented soil around the pile shaft was different from that at the enlarged pile base; the stress in the cemented soil around the shaft increased suddenly when nearing the pile base; the ultimate skin friction obtained in the model test was larger than that estimated in the field test; and the relative displacement between the precast nodular pile and the cemented soil could be ignored during the loading process, which corresponded to the result of the field test and demonstrated that the nodular pile and cemented soil act as one entity during the loading process.     

Vertical dynamic impedance of pile considering the dynamic stress diffusion effect of pile end soil

A new analytical model is presented to analyze the dynamic stress diffusion effect of pile end soil on the vertical dynamic impedance of the pile. The surrounding soil of the pile is modeled by using the plane strain model and the pile is simulated by using one-dimensional elastic theory. Finite soil layers below the pile end are modeled as conical fictitious soil pile with stress diffusion angle which reflects the dynamic stress diffusion effect of pile end soil. By means of the Laplace transform and impedance function transfer method, the analytical solution of the vertical dynamic impedance at the pile head in frequency domain is yielded. Then, a comparison with other models is performed to verify the conical fictitious soil pile model. Finally, based on the proposed solution, the selected numerical results are compared to analyze the influence of dynamic stress diffusion effect for different design parameters of the soil-pile system on the vertical dynamic impedance at the pile head.     

柔性管道骨架层压溃失效机理和安全评价方法研究进展

非黏结柔性管道作为深水油气开发领域的关键设备,是连接海底井口和海洋平台的主要纽带。海洋油气开发水深已经超过了3 000 m,高静水压力是深水软管设计和安全评价的主要挑战,明确深水柔性管道压溃失效机理,并准确地预测柔性管道的压溃压力可以为柔性管道结构设计和安全评价提供依据,柔性管道的压溃压力与骨架层的几何形状以及骨架层之间复杂的相互作用有关,准确高效地预测压溃压力变得极具挑战性。针对柔性管道失效机理研究和压溃压力预测方法进行了总结,指出当前柔性管道压溃失效分析中薄弱的环节,为我国非黏结柔性管道的结构设计和安全评价提供参考。     

Vertical impedance of tapered piles considering the vertical reaction of surrounding soil and construction disturbance

The pile–soil system is divided into layers of sufficient number such that the shear stiffness at the pile–soil interface can be determined based on the complex stiffness transfer method. The vertical reaction of surrounding soil on the annular projections at the interface of adjacent pile segments is simplified using Voigt model, whose spring and damping coefficients are derived afterward, allowing an amended impedance function transfer method to be proposed. Using the amended impedance function transfer method, the dynamic equilibrium equation of the pile is solved to give an analytical solution for the impedance function at the pile top. By comparing the solution proposed in this paper with other solutions, the superiority of the bearing capacity of a tapered pile is further confirmed. A parameter study is then conducted to give insight into the coupled interaction of the vertical reaction of the surrounding soil with construction disturbance in the low-frequency range concerned in the seismic design of the pile foundations.     

一种越浪式波能发电装置越浪量和波压力的试验研究

越浪式发电装置具有结构稳定、可靠性高等优点。在前人的研究基础上,对越浪式波能发电装置的模型进行了优化设计,通过模型实验研究了该波能发电装置在不同波况、不同干舷高度下对波能的俘获能力以及结构的受力情况。对越浪量的试验结果进行了无量纲分析,分别得出了越浪式模型装置的越浪量关于干舷高度和波高的指数函数拟合曲线,总结了两者对越浪量影响的普遍规律。通过对规则波和不规则波波浪作用下装置受力结果的归纳总结,探讨了波能装置波压力和浮托力变化的一般规律。本研究可为越浪式波能发电装置的研究提供参考依据,为波浪能的利用提供一定的参考价值。     

斜向波对直立式防波堤堤头作用的试验研究

直立式防波堤堤头在斜向波浪作用下波浪力的计算在现行的技术规范中尚属空白。通过物理模型试验给出了堤头结构设计所需的波压分布图，指出了波浪入射方向和地形对堤头所受波浪力的贡献有时可以超过波高和波周期，根据现行规范按波浪正向入射计算堤头所受的波浪力偏于安全。