水下插桩定位系统在导管架吊装中的应用

针对海上导管架吊装水下插桩到海底已有钢管桩内的作业难点,通过使用高精度定位设备、罗经、姿态仪和无线网桥,组建集测量导管架位置、高程、方位和姿态于一体的三维定位系统,接入定位软件中,实现实时显示导管架的位置、高程、方位、姿态和导管架桩腿插尖分别距每个海底钢管桩的平面距离和垂直距离,用于指导导管架吊装作业。在广东阳江某海上风电项目中,将该定位系统应用于风机导管架吊装作业中,实现了数字化和可视化作业指导,快捷地完成吊装作业,对后续类似项目具有参考意义。     

导管架平台桩基贯入深度的两级模糊模式优选模型

桩基础是海洋导管架平台结构中的重要组成部分，其贯入深度对海洋平台的造价和运营期间的安全性能起着重要的影响。本文在考虑桩－土之间相互作用非线性特性的基础上，采用非线性等效弹筑模拟海底土层对桩基的作用，对桩基进行有限元分析。由于影响海洋导管架平台桩基础贯入深度的因素很多，而且有些因素带有很大的模糊性，本文采用两级模糊模式优选模型对影响因素进行综合评判，最后得出了适合给定荷载和海底地条件下最为合理的桩基贯入深度方案，具有一定的工程应用价值。     

自升式钻井平台插桩深度探析

针时目前带桩靴的自升式桩基平台插桩深度计算中存在的问题,通过考虑插桩过程中桩靴对地层物理力学性质的影响,运用最小二乘法求得桩靴对地层承载力的影响系数,从而时Terzaghi和Peck公式进行修正,提高插桩深度预测的准确性.     

插桩引起的黄河水下三角洲工程地质条件变化——以埕岛油田区为例

黄河三角洲埕岛油田开发中,平台就位作业一般采用插桩基础,对井场的海底地貌、浅表地层产生扰动破坏,拔桩后形成桩穴,桩穴重新充填后,地基土工程性质会发生变化.通过对平台拔桩移走后的海底场地进行水深测量、浅地层剖面特征调查以及场地中桩穴内外地层工程地质条件的对比分析,给出了埕岛油田海域因插桩引起的工程地质条件变化特征,并对桩穴内外工程地质条件的变化成因进行了分析.     

考虑隔水导管群桩基作用的导管架平台强度分析方法

本文探讨了导管架平台结构强度分析一种改进方法。在该方法中,考虑了隔水导管群刚度和桩基作用,同时考虑了隔水导管之间以及隔水导管与主桩之间的群桩效应以及上部结构－桩－土相互作用。通过对某六腿导管架平台的分析表明,改进方法可以给出比常规方法更合理的结果。     

潮间带钢管斜桩吊打导向装置与沉桩参数研究

钢管斜桩是潮间带风电的常用基础形式,常采用吊打沉桩的方式。文章针对潮间带吊打沉桩方式的难点开发吊打导向装置,并总结沉桩参数的确定方法。该导向装置包括定位桩、定位架和调向限位架,总体平面布局为六边形,可一次定位并完成整个风电基础的基桩施工,既能可靠保证桩的施工精度,又能极大地提高施工效率和降低安全风险;在应用该施工关键装备时,采用GRLWEAP打桩分析功能确定桩顶动荷载,采用有限元软件建立导向装置有限元模型,对导向装置和沉桩参数进行分析,从而实现斜桩顺利沉桩的目的。该装置和方法已成功应用于越南朔庄一期海上风电场项目,为潮间带风电钢管斜桩吊打施工提供沉桩装备和方法经验。     

非灌浆导管架平台异常振动的测试分析及故障诊断

通过对平台在风浪作用下的振动测试分析,发现了直立式非灌浆桩腿导管架平台在海底冲刷条件下发生异常振动的原因是导管架与桩之间存在较大的相对运动,以至于在风浪较大时发生碰撞。因而,结构的动力特性和动态响应都与设计结果不一致。在非极值海况条件下,平台的振动超出了设计预测值,并提出了治理和设计建议。     

不同浪向的波浪载荷作用下导管架平台主桩强度分析

以包括泥面以下桩基在内的所有杆件所构成的桁架式导管架平台为对象,首先通过数值模拟计算组成导管架平台的每一构件的波浪载荷,然后以有限元算法建立包含了平台桩基土反力等因素的导管架整体结构的力学模型,将计算所得波浪载荷施加到该有限元力学模型上,以此通过数值计算手段分析平台中包括泥面以下主桩在内所有杆件的最大应力分布以及桩基的位移特征,从而对平台在特定的波浪环境下的平台主桩的安全性问题进行观察。所提出的方法可为导管架平台在波浪环境下主桩的强度特征分析提供一种实用手段。     

单一地层平台插桩地基土破坏模式及插桩深度有限元分析

自升式平台插桩是地基土在桩靴荷载作用下发生连续塑性破坏的过程,当地基极限承载力等于桩靴荷载时插桩完成。经典土力学极限承载力理论对土体潜在滑动面做了假设,无法有效分析土体内部的破坏过程。因而,研究采用有限元极限分析法对单一地层中插桩时地基土渐进破坏过程进行了模拟,并与Skempton、Terzaghi公式计算的极限承载力进行了对比,取得了较为一致的结果,同时对插桩深度进行了预测。     

复杂地层下土塞破坏模式在大型自升式钻井平台插桩中的应用

自升式钻井平台在海洋石油开采中得到了广泛的应用。桩腿的刺穿安全性分析是钻井平台插桩分析的重点。随着钻井平台建造越来越大,压载过程中,桩靴对土层的破坏模式也发生了改变,一种新的土层破坏模式(土塞破坏模式)在大直径桩靴压载过程中经常发生。分析了在复杂地层下,常规破坏模式和土塞破坏模式发生的机理,并对土塞破坏模式下计算桩靴入泥深度的基本公式进行了介绍。根据多次工程实践以及案例分析表明,土塞破坏分析模式能够较为准确地预测大型钻井平台在复杂地层下的桩靴入泥深度,为钻井平台操作者提供可靠的资料和安全分析。     

Model of the post-Cenozoic evolution of the cryolithozone of the shelf of the western part of the Laptev Sea

The analysis of the structure of the cryolithozone, facies, and thicknesses of the Quaternary sediments and the results of the physicochemical mathematical modeling of the modern shelf of the western part of the Laptev Sea support the influence of the Late Pleistocene glaciations on the heat conditions and the distribution of the permafrost in the area. A ～200-m thick glacier formed under aerial conditions from atmospheric precipitation represented the metamorphosed snow cover. According to the modeling, the long-living (from 60?50 to 10?4 ky) glacier reduced the thickness of the permafrost rocks in the reviewed shelf area for 280–360 m. The Holocene marine transgression additionally decreased the thickness from 50–140 m on the inner shelf to 220–350 m on the outer shelf. The modern submarine cryolithozone 450-0 m thick is wide-spread in the studied region from the coast to the shelf boundary (isobaths of 130–140 m), where it pinches out at a distance of ～380 km from the coast at a depth of ～250 m above the sea level.     

Investigation of the mechanism of the long-term evolution of the carbon cycle in the ecosystem of the Sevastopol bay

We analyze the components of the carbon system of the Sevastopol bay waters and the balance of main sediment-forming substances using the data of field investigations in 1998–2008. The interannual variations of total inorganic carbon and the equilibrium partial pressure of carbon dioxide in the bay water are noted. An increase in the flux of carbon dioxide into the bay and in the content of organic carbon in bottom sediments is revealed, and an explanation of this phenomenon is given. The priority accumulation of organic carbon in the sediments of the bay is established. We assess the interannual variation in the relative abundances of organic and inorganic carbon as an index of the carbon cycle stability.     

Contemporary state of the investigation of the influence of the discharge of rivers on the hydrologic structure of the Black Sea

We generalize and analyze the state of investigations of the influence of river waters on the hydrologic structure of the Black Sea. Specific features of the water, regime and hydrography of rivers flowing into the sea, data on the discharge of rivers, and intrayear and interyear variability of the discharge are presented. We discuss and analyze works studying the transformation of river waters, routes of desalinized sea waters, and their influence on the thermohaline structure and dynamic regime of the sea. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Modelling of the ecosystem of the Black-Sea shelf zone near the estuary of the Danube

We analyze the results of numerical calculations performed according to the three-dimensional interdisciplinary model of an ecological system of the Black-Sea shelf zone near the estuary of the Danube. The complete system of equations of hydrothermodynamics is solved together with transport equations of the advection-diffusion-reaction type used to describe the transformation of a substance (nitrogen) between the components of the characteristic vectors of the ecosystem: plankton, detritus, and biogenic elements (nitrates). We describe the distinctive features of the circumcontinental distribution of components obtained as a result of numerical experiments and present arguments for the conclusion that the ecosystem of the Danube estuary water area plays the role of a buffer zone between the press of the Danubian biogenic pollutions and the neighbouring areas of the shelf zone and open sea. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Dynamics of the ice cover and peculiarities of the ice transportation of the sediments at the tidal flats of the Kandalaksha Gulf of the White Sea

Ten years of semistationary studies of the interaction of the ice cover and the coastal relief of the Kandalakhsa Gulf in the White Sea allowed us to reveal the peculiarities of these processes in the warm and cold years and the mechanisms of the origination of ice forms, including ice tents, which govern the character of the tidal flats. Three dynamic fast ice zones are distinguished by their geomorphological location, morphology, and ice dynamics. The dependence of the mechanisms and volumes of the enrichment of the fast ice in the sediments on the coastal zone??s relief was established. At the coast of the Kindo Peninsula (Velikaya Salma Strait), the ice mostly contains fine-sandy sediments. Coarser sediments, including boulders, are occasional and frozen into the ice at the contact of the fast ice and the bottom. At the expense of the ice??s spreading by 4?C6 times in the warm years and 2?C4 times in the cold years, several thousand tons of sediments mostly from the tidal flat??s surface (100?C700 m³ from 1 km of coast in the wide tidal flats and <50 m³ on the steep coasts) are delivered to the water area.     

Relationship between the path of the Kuroshio in the south of Japan and the path of the Kuroshio Extension in the east

A relationship between paths of the Kuroshio and Kuroshio Extension (KE) is investigated, using the satellite-derived altimetry dataset of 1993–2008. When the Kuroshio takes the nearshore nonlarge meander path or typical large meander path and resultantly goes through the deeper channel (about 2500 m) of the Izu-Ogasawara Ridge, the KE path adopts a relatively stable state with the two quasi-stationary meanders. On the other hand, when the Kuroshio takes the offshore nonlarge meander path and then passes over the shallower part of the Ridge (about 1000 m), the KE path tends to be convoluted, i.e., an unstable state.     

A model of the dynamics of the ecosystem of the Sea of Azov

We use many-year archival observations of hydrologic and hydrobiologic state of the Sea of Azov for the identification of the structure of a model of its ecosystem. The ecosystem model, supplemented with expert estimates of bioresource consumption (fish reserve), contamination level, and possible ecologic fines for violation of the sea natural state, is formalized by the method of system dynamics. Hereat, the major part of influence functions is found in terms of observational data with application of self-organization algorithms. We also present the results of simulated experiments with the model of the ecosystem, which enable us to analyse scenarios of its behaviour under the influence of various external factors (wind, river discharge, water exchange with the Black Sea, etc.). Translated by Peter V. Malyshev and Dmitry V. Malyshev     

On the Relationship between the Characteristics of the Annual Variations of the Virtual Height of the Ionospheric Sporadic E Layer with the Seasonal Rearrangements of the Stratomesospheric Circulation

Izvestiya, Atmospheric and Oceanic Physics - Analysis of the temporal variations of the virtual heights of the sporadic E layer (h?ES) determined from ionograms with increased accuracy (1...     

Parameters of the sediments of the deep-water basin of the Black Sea

The methodology and the first results of the computations of the volumes, masses, and growth rates of the sedimentary body of the buried Black Sea basin are presented. Their temporal evolution reflects the regional paleogeodynamics, in particular, the reorientation of the vector of the relative movement of the Arabian and Eurasian lithospheric plates and the related intensification of their collision in the late Miocene-Pliocene.     

Variability of the nutrient runoff of the rivers of the Arctic Basin

The spatiotemporal variability of the hydrochemical composition of the riverine runoff in nearmouth areas is presented using the example of selected rivers of the Arctic Basin. The temporal dynamics of the riverine nutrient runoff are mainly determined by the seasonal and interseasonal variations in the drainage basins. The spatial variations in the chemical composition of riverine waters in the near-mouth areas are mainly caused by the dynamics of the water flow and the river bed relief and, to a lesser degree, by biochemical processes. It is shown that the variations in the nutrient composition of the waters in near-mouth areas are comparable in magnitude to those at the river-sea geochemical barriers.