Semi-analytical solutions of groundwater flow in multi-zone (patchy) wedge-shaped aquifers     

《Advances in water resources》2015

Alluvial fans are potential sites of potable groundwater in many parts of the world. Characteristics of alluvial fans sediments are changed radially from high energy coarse-grained deposition near the apex to low energy fine-grained deposition downstream so that patchy wedge-shaped aquifers with radial heterogeneity are formed. The hydraulic parameters of the aquifers (e.g. hydraulic conductivity and specific storage) change in the same fashion. Analytical or semi-analytical solutions of the flow in wedge-shaped aquifers are available for homogeneous cases. In this paper we derive semi-analytical solutions of groundwater flow to a well in multi-zone wedge-shaped aquifers. Solutions are provided for three wedge boundary configurations namely: constant head–constant head wedge, constant head–barrier wedge and barrier–barrier wedge. Derivation involves the use of integral transforms methods. The effect of heterogeneity ratios of zones on the response of the aquifer is examined. The results are presented in form of drawdown and drawdown derivative type curves. Heterogeneity has a significant effect on over all response of the pumped aquifer. Solutions help understanding the behavior of heterogeneous multi-zone aquifers for sustainable development of the groundwater resources in alluvial fans.  相似文献   

Boundary element analysis of axially loaded piles embedded in a multi-layered soil   总被引：1，自引：0，他引：1  

Z.Y. Ai  J. Han 《Computers and Geotechnics》2009

In a field, piles are likely installed in a multi-layered soil. Analysis of axially loaded piles in a multi-layered soil is complicated and deserves more attention. A boundary element method is used in this study to analyze an axially loaded single pile in a multi-layered soil using the solution for vertical and horizontal axisymmetric ring loads in a multi-layered elastic medium. Good and reasonable agreement is obtained between the proposed and published solutions for a single pile in a homogenous soil, a finite soil, and a Gibson soil. The proposed solution is also used to evaluate an axially loaded single pile in a multi-layered (8 layers) soil.  相似文献   

An optimal procedure for deriving marine gravity from multi-satellite altimetry     

Cheinway Hwang  Barry Parsons 《Geophysical Journal International》1996,125(3):705-718

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The Green’s function of the harmonic horizontal force applied at the interior of the saturated half-space soil     

Lu Jian-fei  Wang Jian-hua  Shen Wei-ping 《地震学报(英文版)》2001,14(2):196-202

By using integral transform methods, the Green’s functions of horizontal harmonic force applied at the interior of the saturated half-space soil are obtained in the paper. The general solutions of the Biot dynamic equations in frequency domain are established through the use of Hankel integral transforms technique. Utilizing the above-mentioned general solutions, and the boundary conditions of the surface of the half-space and the continuous conditions at the plane of the horizontal force, the solutions of the boundary value problem can be determined. By the numerical inverse Hankel transforms method, the Green’s functions of the harmonic horizontal force are obtainable. The degenerate case of the results deduced from this paper agrees well with the known results. Two numerical examples are given in the paper. Foundation item: State Natural Science Foundation (59879012) and Doctoral Foundation from State Education Commission (98024832).  相似文献   

南京长江二桥八卦洲引线路基沉降观测和数据分析   总被引：1，自引：0，他引：1  

黄腾  郑玉华  郭志明 《测绘工程》2003,12(1):44-46

结合南京长江二桥八卦洲引线的路基沉降观测，对观测设施的布设、观测的技术要求等各项工作作了必要的介绍，采用统计方法对观测成果进行分析，以确定点位的稳定性，最后运用傅里叶变换方法分析测量数据时间序列在频率域上的变化特性，并在此基础上对可能存在的沉降规律作出分析，目的在于为工程管理部门提供决策依据，也用于指导类似工程的沉降观测工作。  相似文献   

Dealing with Compositional Data: The Freeware CoDaPack   总被引：2，自引：0，他引：2  

S. Thió-Henestrosa  J. A. Martín-Fernández 《Mathematical Geology》2005,37(7):773-793

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Criteria to Compare Estimation Methods of Regionalized Compositions   总被引：1，自引：0，他引：1  

J. A. Martín-Fernández  R. A. Olea-Meneses  V. Pawlowsky-Glahn 《Mathematical Geology》2001,33(8):889-909

The additive logratio (alr) transformation has been used in several case studies to predict regionalized compositions using standard geostatistical estimation methods such as ordinary kriging and ordinary cokriging. It is a simple method that allows application to transformed data all the body of knowledge available for geostatistical analysis of coregionalizations without a constant sum constraint. To compare the performance of methods, it is customary to use a univariate crossvalidation approach based on the leaving-one-out technique to evaluate the performance for each attribute separately. For multivariate observations this approach is difficult to interpret in terms of overall performance. Therefore, we propose using appropriate distances in real space and in the simplex, to improve the crossvalidation approach and, going a step forward, to adapt the concept of stress from multidimensional scaling to obtain a global measure of performance for each method. The Lyons West oil field of Kansas is used to illustrate the impactof using different distances in the performance of ordinary kriging versus ordinary cokriging.  相似文献   

Isostatic response of the Alula-Fartak and Owen transforms in the Eastern Gulf of Aden and the adjoining Arabian Sea     

M. Radhakrishna  R. C. Searle 《Geophysical Journal International》2006,165(1):62-72

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The assessment of multi-sensor image fusion using wavelet transforms for mapping the Brazilian Savanna   总被引：2，自引：0，他引：2  

F.W. Acerbi-Junior  J.G.P.W. Clevers  M.E. Schaepman 《International Journal of Applied Earth Observation and Geoinformation》2006,8(4):278-288

Multi-sensor image fusion using the wavelet approach provides a conceptual framework for the improvement of the spatial resolution with minimal distortion of the spectral content of the source image. This paper assesses whether images with a large ratio of spatial resolution can be fused, and evaluates the potential of using such fused images for mapping the Brazilian Savanna. Three types of wavelet transforms were used to perform the fusion between MODIS and Landsat TM images. Five quality measures were defined to assess the quality of the fused images. The results showed that it was possible to perform the fusion of MODIS and TM images and the pyramidal in Fourier space wavelet transform provided the best quality measures for the fused images. Classification results showed that fused images could be used for mapping the Brazilian Savanna with an accuracy level comparable to the Landsat TM image.  相似文献   

利用双正交小波变换去除图象噪声     

于亦凡 《中国海洋大学学报(自然科学版)》2002,32(5):833-836

对噪声污染的图象进行复原处理时 ,传统的去噪声方法会造成图象模糊。本文用双正交小波变换去除图象噪声 ,从结果看利用双正交小波变换进行多分辨率低通滤波在去除噪声的同时造成的模糊比传统低通滤波器少  相似文献