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1.
自由落体贯入仪(free falling penetrometer,简称FFP)通过自由下落贯入土层中,由于其高效便捷的特性,越来越广泛地被应用于海底浅层土体原位勘察。采用耦合欧拉-拉格朗日(Coupled Eulerian Lagrangian,简称CEL)方法,进行了球形FFP在硬-软双层黏土中贯入的大变形有限元分析,考虑了土体的应变率和应变软化效应。与离心机试验、现场试验和数值模拟结果进行了对比,验证了模型的可靠性。分析了成层土对贯入过程的影响,发现FFP在贯入过程中上部硬黏土层形成空腔,且底部会伴随着土塞。通过广泛的变参数分析结果,拟合了球形FFP最终贯入深度与总能量之间的归一化表达式,建立了土体不排水抗剪强度、FFP直径和贯入速度与FFP在硬-软黏土层中最终贯入深度的关系。  相似文献   

2.
王焕松  雷坤  李子成  张峥  周莉 《海洋学报》2011,33(6):110-116
利用辽河、大辽河、小凌河1992-1995,2004-2007年,大凌河1995-2007年的水文和水质入海监测资料,估算了辽东湾北岸四条主要入海河流各污染因子的入海通量,并初步分析了污染物通量年际变化的影响因素.结果表明,辽东湾北岸的四条主要河流中除小凌河各种污染物入海通量总体上呈增加趋势以外,其他三条河流各污染物的...  相似文献   

3.
黄河是中国第二长河,其形成和演化对中国地貌格局的演化和古气候变化具有重要的指示意义。19世纪以来,陆续有学者提出黄河在沿三门峡入海之前曾由河套盆地向东经由永定河入海的猜想,这一假想的河流可称为“北黄河”。这一猜想在地理学领域有较广泛的影响,然而,一直以来却鲜有证据明确证实或证伪这一猜想。本文综合新近发表的华北平原钻孔物源证据、汾渭盆地沉积和三门峡地区的地貌证据对这一猜想进行了探讨。这些证据表明,在约1.6 MaBP之前,位于永定河冲积扇及渤海湾沿岸的所有钻孔均未接收到来自黄河上游和中游的物质,表明此阶段三门峡和北黄河都未开通;而在约1.6 MaBP后,黄河上游和中游的物质开始进入渤海湾,但永定河冲积扇仍缺乏来自黄河上游和中游的物质。结合汾渭盆地三门组在约1.6 Ma快速结束并转变为黄土沉积的证据判断:黄河在约1.6 Ma以前尚未贯通,在约1.6 Ma以后经由三门峡进入华北平原东流入海,即黄河从未经由永定河入海。  相似文献   

4.
以2006-2008年的南四湖4条入湖河流水质监测数据为基础,以溶解氧、高锰酸盐指数、5日生化需氧量和氨氮作为监测项目,采用综合水质标识指数评价法对南四湖入湖河流进行水质评价.结果表明,除泗河监测断面水质为Ⅲ类水体外,其他都属于Ⅳ、Ⅴ类水体,污染较为严重.本研究可为南四湖主要入湖河流的污染治理提供一定的科学依据.  相似文献   

5.
随着工农业生产迅速发展和人口剧增,海岸带经济开发地区淡水资源的利用和科学管理已成为当务之急。由于海岸带地区大多处于许多大河流的末梢,是源远流长的河流淡水人海的尾闾,这也成为有水可供的得天独厚的条件。经过多年的工程实践,水利工  相似文献   

6.
黄河入海水沙通量变化规律   总被引:8,自引:1,他引:8  
根据利津站1950-2003年的水、沙实测资料,采用水文学和数理统计学相结合方法,对黄河入海水沙通量进行分析,分别得出了水、沙通量的年代变化、年际变化、季节变化规律以及水、沙通量之间关系.结果表明:黄河入海水、沙通量递减趋势明显,尤其在近20a来这种趋势更加显著;年际、年内沙量变化幅度都大于水量;黄河入海水沙主要集中在汛期,汛期与非汛期的水沙量差异将会持续减小;年输沙量和年径流量、多年平均月输沙量和径流量分别以乘幂、多项式回归,各月多年输沙量和径流量以多项式、指数回归,相关性都很高.  相似文献   

7.
吴溪 《海洋世界》2007,(11):12-15
"看这儿——冰岛的西部海岸,你看见冰岛的首都雷克雅未克了吗?看见了!好,再顺着受海水侵蚀的海岸旁的这些数不清的峡湾往上看,注意纬度65°下面一点的地方,你看见什么东西了吗?""有一个好像一根瘦瘦的骨头似的半岛,尽头像一根巨大的膝盖骨的形状。""这个比喻很对,我的孩子。你在这根膝盖骨上看见什么没有?""看见了,一座好像伸到海里去的山。""对!这是斯奈弗。""斯奈弗?""就是它,这座山高约五千英尺,是这个岛上最有名的火山之一——如果它的陷口可以通到地球中心,它的确可以成为地球上最著名的火山了。"——节选自《地心游记》  相似文献   

8.
9.
中国入海河口分类刍议   总被引:7,自引:0,他引:7  
本文在回顾国内外各家河口分类基础上,进一步从流域状况、河流情势、海洋情势和人为作用诸方面,分析了影响河口形态及其冲淤演变的主要因子,得到3个形态分类指标和6个水沙分类指标。运用模糊聚类分析方法进行综合定量分类,得到中国河口的四个基本类型,并首次提出潮径流量比(QF/QR)和潮径流输沙比(SF/SR)两指标作为各类河口的分类判别指标,最后对分类指标作了初步验证,且简述了各类河口的相互关系。  相似文献   

10.
长江入河口区水沙通量变化规律   总被引:42,自引:6,他引:36  
根据大通站1950-1985年的水、沙实测资料,运用统计分析方法研究长江入河口区水、沙通量的季节性变化、年际变化以及水、沙通量之间的关系。结果表明,长江入河口区的水沙通量有明显的季节性变化,其中沙通量的变化更为显著;丰水年很少连续出现,枯水年有75%以连续两年的形式出现;多沙年的出现形式有1年出现一次的,也有2-3年出现的,少沙年基本上以连续2-3年的形式出现;水沙通量间的相关性较差,其中细颗粒泥  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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  相似文献   

14.
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  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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...  相似文献   

18.
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  相似文献   

19.
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.  相似文献   

20.
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.  相似文献   

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