共查询到20条相似文献，搜索用时 31 毫秒
1.
Zekai Sen 《Mathematical Geology》1989,21(8):891-903
The cumulative semivariogram approach is proposed for modeling regionalized variables in the geological sciences. This semivariogram is defined as the successive summation of half-squared differences which are ranked according to the ascending order of distances extracted from all possible pairs of sample locations within a region. This procedure is useful especially when sampling points are irregularly distributed within the study area. Cumulative semivariograms possess all of the objective properties of classical semivariograms. Classical semivariogram models are evaluated on the basis of the cumulative semivariogram methodology. Model parameter estimation procedures are simplified with the use of arithmetic, semilogarithmic, or double-logarithmic papers. Plots of cumulative semivariogram values vs. corresponding distances may scatter along a straight line on one of these papers, which facilitates model identification as well as parameter estimation. Straight lines are fitted to the cumulative semivariogram scatter diagram by classical linear regression analysis. Finally, applications of the methodology are presented for some groundwater data recorded in the sedimentary basins of the Kingdom of Saudi Arabia. 相似文献
2.
On the Use of Non-Euclidean Distance Measures in Geostatistics 总被引：4，自引：0，他引：4
Frank C. Curriero 《Mathematical Geology》2006,38(8):907-926
In many scientific disciplines, straight line, Euclidean distances may not accurately describe proximity relationships among
spatial data. However, non-Euclidean distance measures must be used with caution in geostatistical applications. A simple
example is provided to demonstrate there are no guarantees that existing covariance and variogram functions remain valid (i.e.
positive definite or conditionally negative definite) when used with a non-Euclidean distance measure. There are certain distance
measures that when used with existing covariance and variogram functions remain valid, an issue that is explored. The concept
of isometric embedding is introduced and linked to the concepts of positive and conditionally negative definiteness to demonstrate
classes of valid norm dependent isotropic covariance and variogram functions, results many of which have yet to appear in
the mainstream geostatistical literature or application. These classes of functions extend the well known classes by adding
a parameter to define the distance norm. In practice, this distance parameter can be set a priori to represent, for example,
the Euclidean distance, or kept as a parameter to allow the data to choose the metric. A simulated application of the latter
is provided for demonstration. Simulation results are also presented comparing kriged predictions based on Euclidean distance
to those based on using a water metric. 相似文献
3.
Pfannkuch Hans-Olaf Mooers Howard D. Siegel Donald I. Quinn John J. Rosenberry Donald O. Alexander Scott C. 《Hydrogeology Journal》2021,29(6):2001-2015
The interpretation of aquifer responses to pumping tests is an important tool for assessing aquifer geometry and properties, which are critical in the assessment of water resources or in environmental remediation. However, the responses of aquifers, measured by time-drawdown relationships in monitoring wells, are nonunique solutions that are affected by many factors. Jacob’s Zoo is a collection of graphical interpretations that allows students and practitioners to develop an intuitive feel for how natural hydrogeological systems work, and develop a set of skills that provide a better understanding of aquifer properties far beyond interpretation of pumping tests. Jacob’s Zoo, based on the work of Jacob (1950), fosters a deeper understanding, although few practitioners realize the full utility of the method. Jacob CE (1950) Flow of groundwater, In: Rouse H (ed) Engineering Hydraulics, Wiley, New York. P 321–386.
相似文献4.
Global curve-fitting for determining the hydrogeological parameters of leaky confined aquifers by transient flow pumping test 总被引：4，自引：1，他引：3
Proper management of groundwater resources requires an accurate evaluation of the parameters (hydraulic properties) that control the movement and storage of groundwater. Hydrogeological parameters are the basis of groundwater evaluation, modeling, and management and so on. A global curve-fitting method incorporating pumping test data and water table recovery data was introduced in the present study. The principal and procedures of the method were elucidated in detail. The drawdown and recovery data from two sets of transient flow pumping test conducted in no. 2 water source site of Shizuishan city were used to verify the calculation accuracy of the proposed method. The hydrogeological parameters were also estimated with traditional type curve-fitting method on the basis of formula derived by Hantush and Jacob. The hydrogeological parameters calculated by the two methods were compared and the results show that the parameters obtained by the global curve-fitting method are a little bigger than but very close to those obtained by the traditional type curve-fitting method. The proposed method which possesses three major advantages is feasible and reliable in aquifer parameter identification. A comparative study on various methods for parameter identification is required and expected in future study. 相似文献
5.
通过对一个滨海多层含水层系统的考察,该含水层系统由上、下弱透水层和介于中间的承压含水层组成,海底露头处被淤泥层覆盖.建立了描述该系统中地下水水头随潮汐波动的数学模型,并得到其解析解.该解析解与六个基本参数有关,分别是承压含水层的海潮传播参数,淤泥层的无量纲透水系数,上下弱透层与承压含水层贮水率的比率 (无量纲)和上下弱透层的无量纲越流.当这些参数取某些特殊值时,我们的解便化简为前人考虑的几种简单情形对应的解.分析表明,承压含水层中地下水水头波幅是上、下弱透水层贮水率和越流系数的减函数,是淤泥层相对透水系数的增函数;波动相位(时滞)是上、下弱透水层贮水率和越流系数的增函数,是淤泥层相对透水系数的减函数. 相似文献
6.
7.
为评价振荡试验在获取倾斜承压含水层水文地质参数过程中含水层倾角对计算结果的影响,基于Kipp模型推导了考虑承压含水层倾角的振荡试验解析解模型。倾斜承压含水层量纲一贮水系数和量纲一导水系数不变条件下,测试井-含水层系统的量纲一阻尼系数随着倾角的增加而增加。修正模型计算的量纲一阻尼系数与Kipp模型计算的量纲一阻尼系数偏差10%以上时,必须考虑倾角的影响并且承压含水层倾角对水头响应曲线造成影响临界角度约为34°。修正模型和Kipp模型对现场振荡试验水头响应曲线分析结果的差异表明,忽略含水层倾角会对倾斜承压含水层导水系数和贮水系数的计算结果产生较大误差。 相似文献
8.
A simple parameter estimation procedure, designated as integration-based estimation (IBE), was introduced to determine the hydraulic properties of an aquifer using slug test models subjected to certain flow geometries such as radial and spherical flows. The basic idea behind the proposed IBE approach is to link an integration value at pre-defined normalized head levels for field data with that of a theoretical type curve. The IBE method removes the need for the implementation of the classical graphical matching process which would be ineffective to acquire aquifer parameters for non-ideal aquifer conditions. As the second aspect of this study, a new decision tool was suggested to determine the suitable slug test model to be utilized for the site data since diagnosing the flow character properly is of crucial importance for following a convenient analysis procedure. The estimation performance and limitation of the proposed IBE method were tested for several slug test scenarios including radial and spherical flow models with a number of synthetically generated data sets as well as a field application. Results reveal that the IBE together with the identification methodology not only is able to retrieve aquifer parameters as reliable as the existing techniques in the literature but also diagnoses the flow character precisely as demonstrated in this study. 相似文献
9.
含水层参的反演是一个复杂的非线性优化问题，针对传统二进制遗传算法收敛性能差的缺陷，提出了反演含水层参数的十进制遗传算法.以直线隔水边界附近的井流模型为例，讨论了十进制遗传算法在含水层参数反演中的应用，并与二进制遗传算法的进行比较.结果表明，该方法在含水层参数的反演中不仅是可行的，而且具有较好的确定性和较高的精度;与二进制遗传算法相比，十进制遗传算法的收敛性较好，省时高效，且表示较为自然，容易引入相关领域知识.同时，结合实例的分析结果得出种群的规模对算法的收敛性没有明显的影响。 相似文献
10.
The dependence of stream depletion by seasonal pumping on various hydraulic characteristics and engineering factors 总被引：3，自引：2，他引：1
Compensation pumping is used to alleviate deficiencies in streamflow discharge during dry seasons. Short-term groundwater pumping can use aquifer storage instead of catchment-zone water until the drawdown reaches the edge of the stream. The capacitance is a complex, dimensionless parameter of an aquifer system that defines the delayed effect on streamflow when there is groundwater pumping. This parameter is a function of aquifer hydraulic characteristics, pumping time, and distance between the well and stream edge; the latter can involve stream leakance and vertical leakance of an associated aquitard. Three typical hydraulic cases of combined water systems (major catchment-zone wells close to the stream and compensation pumping wells) were classified depending on their capacitance structure (i.e. the relationship between surface water and groundwater): (1) perfect hydraulic connection between the stream and aquifer; (2) imperfect hydraulic connection between the stream and aquifer; and (3) essentially imperfect hydraulic connection between the stream and the underlying confined aquifer. The impact of various hydraulic characteristics and engineering factors on stream depletion was examined by conceptual and numerical modeling. To predict the suitability and efficiency of a combined water system application, regression tests were undertaken on unit stream depletion and capacitance, and power dependencies were defined. 相似文献
11.
含水层的水文地质参数是进行地下水资源计算、地下水污染防控等所必需的基础数据,结合数值模拟技术进行含水层参数反演很有必要.按照1:5万水文地质调查规范在江汉平原仙桃市杨林尾镇复兴水厂不同含水层位开展抽水试验,包括深层含水层单孔抽水试验以及浅层含水层中群孔(2孔)抽水试验.对于单孔抽水试验,应用第1类越流系统井流理论进行参数反演;对于群孔抽水试验,推导了特定综合井函数,并利用特定标准曲线匹配法和直线图解法求解了含水层参数.随后利用FEFLOW软件建立了相应数值模型,拟合了含水层参数.结果表明:浅层含水层的渗透系数变化范围为21.66~54.00 m/d,贮水率变化范围为1.28×10-5~8.00×10-4 m-1;深层含水层渗透系数变化范围为1.27~7.00 m/d,贮水率变化范围为3.90×10-6~5.00×10-6 m-1.对于深层承压含水层而言,越流补给量较大.采用数值模拟方法结合抽水试验数据求参,综合考虑了含水层结构,拟合效果好,所得结果更加可靠. 相似文献
12.
由于强烈的非均质性,如何识别岩溶裂隙含水层水文地质参数是一个由来已久的难题。本文利用焦作矿区、荥巩矿区及永夏矿区生产矿井大流量、长时间的排水资料进行识别岩溶裂隙水含水层的水文地质参数,计算结果发现：K值均在100m/d量级上,μ＊值均在10^-3量级上,与孔隙含水层的值相当;用识别的参数预算矿井涌水量与区域降雨补给量接近,回报水位及给定条件下排水量误差均不超过2%。结果表明,可以用渗流理论模型对管道流、裂隙流进行概化处理。研究成果提出矿区岩溶裂隙地下水参数计算的新方法,为防控矿坑突水、安全生产提供了新思路。 相似文献
13.
Rogers Martina Sukop Michael C. Obeysekera Jayantha George Florence 《Hydrogeology Journal》2023,31(4):1031-1049
The Biscayne Aquifer (Florida, USA) is a coastal, shallow, unconfined, and heterogeneous aquifer with high water tables, composed of less-permeable sand to highly permeable karstic limestone. These properties make the Biscayne Aquifer one of the world’s most productive groundwater resources. The aquifer’s high yield and non-Darcian flow cause challenges for estimating aquifer parameters, which are essential for understanding groundwater processes and managing and protecting the groundwater resources. Water-table fluctuations in the Biscayne Aquifer are associated with astronomical tidal forces and gate operations on canal water-control structures. Analysis of observed groundwater level fluctuations can provide an understanding of the connectivity between the aquifer, Biscayne Bay, and the water level in the canals. Further, groundwater level fluctuations can be used for aquifer parameter estimation. In this research, observed ocean water levels measured at tidal stations and groundwater levels are fitted to Jacob’s analytical solution, where the amplitude of the groundwater head fluctuation decreases exponentially, and the time lag increases with distance from the shore. Observed groundwater levels were obtained from monitoring wells along the Miami-Dade shore and the barrier island of Miami Beach. Results indicate that Jacob’s solution is effective for aquifer parameter estimation in Miami Beach, where monitoring wells are closer to the shore. Estimated hydraulic conductivity appears to increase by four orders of magnitude to approximately 1 m s–1 as the distance from shore increases. Constructing monitoring wells closer to the shore in Miami-Dade County and elsewhere would permit improved aquifer parameter estimation and support enhanced groundwater modeling efforts.
相似文献14.
In this first part of the work, we develop macroscopic models for migration and diffusion–migration of ionic species in saturated porous media, based on periodic homogenization. The prior application is chloride transport in cementitious materials. The dimensional analysis of Nernst–Planck equation lets appear to dimensionless numbers characterizing the ionic transfer in the porous medium. Using experimental data obtained from electrodiffusion tests on cement‐based materials (Part II), these dimensionless numbers are linked to the perturbation parameter ?. For a strong imposed electrical field, the asymptotic expansion of Nernst–Planck equation leads to a macroscopic model where the migration is predominant. For a weak imposed electrical field or in natural diffusion, we obtain a macroscopic model coupling diffusion and migration at the same order. In both models, the expression of the homogenized diffusion tensor is identical and only involves the geometric properties of the material microstructure. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
15.
含水层参数对于定性分析区域地下水资源评价、数值模拟及预报、开发利用与保护及科学管理具有重要意义,而江汉平原水文地质参数求解的研究却相对较少.2015年江汉平原1:50 000水文地质调查项目完成杨林尾图幅与陆溪口图幅,选择杨林尾图幅和陆溪口图幅中的4个代表性钻孔,分别做了3组抽水试验和一组压水试验.对抽水数据使用Dupuit公式法结合抽水稳定阶段数据求解含水层参数,同时利用Aquifer Test软件中Theis标准曲线法、直线图解法对抽水试验中非稳定条件下抽水数据对含水层参数求解,得到孔隙水含水层渗透系数及弹性给水度;利用压水试验工程规范求解基岩裂隙含水层的渗透系数.探讨了利用非稳定抽水试验条件下求解含水层参数方法的可行性及该方法的优势.计算结果表明:杨林尾镇浅层(20.2~64.55 m)含水层渗透系数为0.075 m/d,弹性给水度为5.8×10-2;深层(138~160 m)含水层渗透系数为9.89 m/d,弹性给水度为2.3×10-5;陆溪口镇浅层(19.4~36.4 m)含水层渗透系数1.26 m/d,弹性给水度为1.1×10-1;基岩渗透系数为0.012 m/d.通过结果对比分析发现对于单孔非稳定抽水试验,对前期水位降深数据筛选分析,同样可以利用非稳定井流理论反演含水层参数,结果比较可靠. 相似文献
16.
Comparison between Neuman (1975) and Jacob (1946) application for analysing pumping test data of unconfined aquifer 
下载免费PDF全文
下载免费PDF全文 Pumping test of a water table aquifer is carried out to estimate the aquifer parameters, the obtained data were analysed through the solution of both Neuman (1975) and Jacob (1946) methods through AQTESOLV and Spreadsheet programs, the results of each methods are compared to evaluate the applicability and accuracy of the solution theoretically and practically. In the paper an example is presented, which is conducted for a constant rate pumping test from Ohio, in Fairborn (near Dayton), and it supplied by S.E. Norris (U.S. Geological Survey, Columbus, Ohio). The main objective of this study is to introduce both program and the way of the applications, and compare the results and the hand on of both programs in the field. 相似文献
17.
Anisotropy and bedding effects on the hydro geological regime in a confined aquifer to design an appropriate dewatering system 总被引：1，自引：1，他引：0
A. Aryafar F. Doulati Ardejani Ph.D. 《International Journal of Environmental Science and Technology》2009,6(4):563-570
Prediction of groundwater inflow into mining excavations is very important in order to design an effective dewatering system to keep the mine workings dry and create prolonged cone of depression. The effects of anisotropy ratio and bedding on the hydraulic head and drawdown curves of a dewatering test carried out in a fully penetrating well in a confined aquifer have been investigated. An existing numerical finite element model has been used to perform the simulations. The results of the numerical model are compared to those from analytical Jacob and Lohman solution for estimating hydraulic heads and drawdown curves. It was found that the anisotropy ratio and bedding should not have a significant effect on drawdown and the quantity of inflow into a confined aquifer. It was further found that taking the simultaneous effects of anisotropy and bedding into account reduces the differences in the results of analytical and numerical methods. Comparison of the field data and model predictions showed that, the modelling results for a three layer anisotropic aquifer fit well to the field data than those results obtained for a single layer aquifer and the relative error decreased from 4.81 % to 2.98 %. 相似文献
18.
开展含水层非均质性数据融合研究 总被引：1，自引：0，他引：1
提出应大力开展含水层非均质性的数据融合研究。指出应充分吸收利用相邻学科已有的研究成果,从易到难,首先应将军事领域已相对成熟的数据融合技术移植过来,开展孔隙含水层非均质性的数据融合研究。论述了含水层非均质性数据融合研究的主要研究思路和研究内容,并展示了初步研究成果。 相似文献
19.
Non-Darcian flow to a well in a leaky aquifer was investigated using a finite difference method. Flow in the leaky aquifer is assumed to be non-Darcian and horizontal, while flow in the aquitard is assumed to be Darcian and vertical. The Forchheimer equation was employed to describe the non-Darcian flow in the aquifer. The finite difference solution was compared with the solution of Birpinar and Sen (2004). The latter overestimates the drawdown at early times and underestimates the drawdown at late times; also, the impact of β D on the drawdown depends on the value of B D, where β D is a dimensionless turbulent factor in the Forchheimer equation and B D is the dimensionless leakage parameter. The impact of leakage on drawdown is similar to that of Darcian flow. A sensitivity analysis indicated that the drawdown is very sensitive to the change in the dimensionless well radius r cD when B D is relatively large, while it is sensitive to the change in B D when B D is relatively small. The numerical solution has been applied to analyze the pumping test data in Chaj-Doab area of Pakistan. Birpinar ME, Sen Z (2004) Forchheimer groundwater flow law type curves for leaky aquifers. J Hydrol Eng 9(1):51??9 相似文献
20.
Emin Ciftci 《Arabian Journal of Geosciences》2018,11(23):761
Flowing well test is one of the tools employed to identify transmissivity and storage coefficient of a confined aquifer where the potentiometric surface is located above the ground surface, so that the groundwater flows naturally from the well without pumping. During a flowing well test, constant hydraulic head is preserved at the well while the discharge from the well decreases with time and the temporal variation of discharge provides significant information about aquifer characteristics. In this study, a simple and straightforward approach is presented as an alternative to a number of graphical or error minimization-based techniques available in the literature for analyzing data from flowing well tests. The proposed method employs a polynomial regression equation to establish a link between observed discharge and the theoretical dimensionless discharge that is introduced in the analytical solution, so as to retrieve the aquifer parameters. The method is tested with a vast number of synthetically generated data sets as well as a real data set reported in the literature. Besides its simplicity, the present method is seen to produce highly accurate and reliable estimations. 相似文献