The state of land subsidence and prediction approaches due to groundwater withdrawal in China   总被引：13，自引：6，他引：7  

Ye-Shuang Xu  Shui-Long Shen  Zheng-Yin Cai  Guo-Yun Zhou 《Natural Hazards》2008,45(1):123-135

This article gives a general introduction to land subsidence with the prediction approaches due to withdrawal of groundwater in three subsided/subsiding regions in China: the deltaic plain of Yangtse River (YRDP), North China Plain (NCP), and Fenwei Plain (FP). On YRDP, Shanghai is the typical subsided/subsiding city; on NCP Tianjin is the typical subsided/subsiding city, and on FP Taiyuan is the typical subsided/subsiding city. The subsided area with subsidence over 200 mm on YRDP is about 10,000 km² and the maximum subsided value reached 2.9 m at Shanghai; on NCP the subsided area reached 60,000 km² with the maximum subsidence of 3.9 m at Tianjing; on FP the subsided area is relatively smaller than that on the other two plains and is about 1,135 km² with maximum subsidence of 3.7 m at Taiyuan city. In order to protect the civil and industrial facilities, it is necessary to predict the future development of land subsidence based on present state. Many researchers proposed several approaches to predict the land subsidence due to groundwater withdrawal according to different geological conditions and groundwater withdrawal practice. This article classifies these approaches into five categories: (i) statistical methods; (ii) 1D numerical method; (iii) quasi-3D seepage model; (iv) 3D seepage model; (v) fully coupled 3D model. In China, the former four categories are presently employed in the prediction practice and their merits and demerits are discussed. According to the prediction practice, 3D seepage model is the best method presently.  相似文献   

Implementation of reconstructed geomorphologic units in landslide susceptibility mapping: the Melen Gorge (NW Turkey)   总被引：6，自引：2，他引：4  

T. Gorum  B. Gonencgil  C. Gokceoglu  H. A. Nefeslioglu 《Natural Hazards》2008,46(3):323-351

In the international literature, although considerable amount of publications on the landslide susceptibility mapping exist, geomorphology as a conditioning factor is still used in limited number of studies. Considering this factor, the purpose of this article paper is to implement the geomorphologic parameters derived by reconstructed topography in landslide susceptibility mapping. According to the method employed in this study, terrain is generalized by the contours passed through the convex slopes of the valleys that were formed by fluvial erosion. Therefore, slope conditions before landsliding can be obtained. The reconstructed morphometric and geomorphologic units are taken into account as a conditioning parameter when assessing landslide susceptibility. Two different data, one of which is obtained from the reconstructed DEM, have been employed to produce two landslide susceptibility maps. The binary logistic regression is used to develop landslide susceptibility maps for the Melen Gorge in the Northwestern part of Turkey. Due to the high correct classification percentages and spatial effectiveness of the maps, the landslide susceptibility map comprised the reconstructed morphometric parameters exhibits a better performance than the other. Five different datasets are selected randomly to apply proper sampling strategy for training. As a consequence of the analyses, the most proper outcomes are obtained from the dataset of the reconstructed topographical parameters and geomorphologic units, and lithological variables that are implemented together. Correct classification percentage and root mean square error (RMSE) values of the validation dataset are calculated as 86.28% and 0.35, respectively. Prediction capacity of the different datasets reveal that the landslide susceptibility map obtained from the reconstructed parameters has a higher prediction capacity than the other. Moreover, the landslide susceptibility map obtained from the reconstructed parameters produces logical results.  相似文献   

海底沉积物分析测试方法标准的研究   总被引：3，自引：0，他引：3  

夏宁  宋苏顷  刘昌岭  张红  林学辉 《海洋科学》2002,26(11):53-56

依据海底沉积物分析测试方法标准研究的总体设计，完成了40个分析项目的21份验证报告，进行了实验室间精密度协作性检验工作，在海底沉积物CaCo3,H2Os^-，H2O^ 的分析方法研究中取得新进展，并建立了ICP－AES法测定海底沉积物中常量、微量、稀土元素分析方法。  相似文献   

光诱鱿鱼浮拖网渔具渔法试验报告     

郑国富??  郑雅友??  戴天元??  洪明苇??  黄桂芳 《海洋科学》2001,25(4):5-8

1989－1999年开展光诱鱿鱼浮拖网渔具渔法研究的生产试验结果为：1998年生产试验86个夜（航次），总产量33．225t，其中鱿鱼产量为12．470t，占总产量的37．5％，总产值139000元，比同村光诱敷网的平均产量（31．62t）高5．1％左右。1999年生产试验80夜（航次），总产量54．66t，其中鱿鱼产量31．92t，占总产量的58．4％，总产值187000元。试验网产量比同村光诱敷网的平均产量（45．64t)增产19．76％，产值增加22．65％，鱿鱼产量占总渔获量的比例提高近10个百分点，投入产出比为1：1．684。取得了较好的试验结果，达到了预期试验目的。此外，文中还讨论了水上灯数量，网具规格和柔性网板等对生产效果和捕捞对象的影响及适应性情况，并建议开展光场强度及其分布的海上实测和光场强度对鱿鱼，趋光性鱼类的行为习性以及生长影响等试验研究，制定出光诱鱿鱼浮报网和敷网作业诱鱼灯数量和分布标准，以合理利用鱿鱼和中上层鱼类资源，实现可持续发展。  相似文献   

莱州湾温带风暴潮预报研究   总被引：1，自引：1，他引：1  

张胜平  徐振山  王军  丁吉龙  侯庆华 《海洋预报》2002,19(1):64-72

本文依据莱州湾羊角沟、夏营两站建国以来的风暴增水资料，对莱州湾建国后发生的风暴潮进行了统计分析，并探讨了温带风暴潮产生的物理机制，此外还对莱州湾温带风暴增水以及诱发增水的天气形势进行了分析分类。在此基础上建立了莱州湾温带风暴潮统计预报方法，并在作业预报中对模型进行了检验，取得较为理想的效果。  相似文献   

Ice-Induced Fatigue Analysis by Spectral Approach for Offshore Jacket Platforms with Ice-Breaking Cones     

岳前进刘圆  张日向屈衍 王瑞学 《中国海洋工程》2007,21(1):1-10

The spectral methods and ice-induced fatigue analysis are discussed based on Miner's linear cumulative fatigue hypothesis and S-N curve data.According to the long-term data of full-scale tests on the platforms in the Bohai Sea,the ice force spectrum of conical structures and the fatigue environmental model are established.Moreover,the finite element model of JZ20-2MSW platform,an example of ice-induced fatigue analysis,is built with ANSYS software.The mode analysis and dynamic analysis in frequency domain under all kinds of ice fatigue work conditions are carried on,and the fatigue life of the structure is estimated in detail.The methods in this paper can be helpful in ice-induced fatigue analysis of ice-resistant platforms.  相似文献   

Triple diagram method for the prediction of wave height and period   总被引：1，自引：0，他引：1  

Mehmet zger  Zekai en 《Ocean Engineering》2007,34(7):1060-1068

Many formulations have been developed so far to predict the wave height and period from fetch length and wind blowing duration for a constant wind speed. This study aimed to predict wave parameters from fetch length and meteorological factors by using triple diagram methodology based on Kriging principles. Proposed model results were compared with Joint North Sea Wave Project (JONSWAP) model which is used so commonly in the ocean and coastal engineering studies. For the implementation of the methodology hourly wave and wind data were obtained from a buoy located in Lake Ontario. Numerical and graphical comparisons demonstrated that the proposed method outperforms the classical formulation.  相似文献   

Reliability of a model based on a short fishery statistics survey: application to the Northeast Atlantic monkfish fishery     

Rocha  Francisco; Gracia  Joaquin; Gonzalez  Angel F; Jardon  Carlos M; Guerra  Angel 《ICES Journal of Marine Science》2004,61(1):25-34

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Performance assessment of a concept propulsor: the thrust-balanced propeller     

Ali Can Takinaci  Mehmet Atlar   《Ocean Engineering》2002,29(2):129-149

This paper presents the results of a numerical performance analysis to demonstrate the worthiness of a recently patented new concept propulsor, the so-called “thrust-balanced propeller (TBP)”. The main advantage of this unconventional propulsor is its inherent ability to reduce the unsteady effect of blade forces and moments when it is operating in a non-uniform wake flow. The propulsor comprises a pair of diametrically opposed blades that are connected to one another and mounted so as to be rotatable together through a limited angle about their spindle axis. A quasi-hydrodynamic approach is described and applied to perform the numerical analysis using a state-of-the-art lifting surface procedure for conventional propellers. Performance comparisons with a conventional fixed-pitch propeller are made for the blade forces and moments, efficiency, cavitation extents and fluctuating hull pressures. Bearing in mind the quasi-static nature of the analyses, the results present favourable performance characteristics for the thrust-balanced propeller and support the worthiness of the concept. However, the concept needs to be proved through physical model tests, which are planned to take in a cavitation tunnel.  相似文献   

Filters for linear sea-wave prediction     

M.R. Belmont  J.M.K. Horwood  R.W.F. Thurley  J. Baker 《Ocean Engineering》2006,33(17-18):2332-2351

Deterministic sea-wave prediction (DSWP) models are appearing in the literature designed for quiescent interval prediction in marine applications dominated by large swell seas. The approach has focused upon spectral methods which are straightforward and intuitively attractive. However, such methods have the disadvantage that while the sea is aperiodic in nature, the standard discrete spectral processing techniques force an absolutely periodic structure onto the resulting sea surface prediction models. As it is the shape of the sea surface that is important in such applications, particularly near the end of the domain which is important, the standard windowing techniques used in signal processing work to reduce leakage artifacts cannot be employed. This has necessitated the use of end matching methods that can be both inconvenient and may reduce the fraction of the time for which legitimate predictions are available. As a result, an investigation has been undertaken of the use of finite impulse response prediction filters to provide the necessary dispersive phase shifting required in DSWP systems. The present work examines the theoretical basis for such filters and explores their properties together with their application to both long and short crested swell seas. It is shown that wide band forms of such filters are only convergent in the sense of distributions having both infinite duration impulse responses and asymptotically divergent first derivatives. However, appropriate band limitation can produce useful finite impulse responses allowing implementation via standard discrete convolution methods. It is demonstrated that despite the prediction filters having a non-causal impulse response such filters can be used in practice due to a combination of the asymmetric nature of the impulse response and the fundamental nature of the prediction process. The findings are confirmed against actual sea-wave data.  相似文献