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本文提出了利用单孔进行弥散实验,确定地下水含水层弥散度的新方法,给出了数学模型、求解过程及方法。提出了用计算机自动处理求得最佳参数的直线回归法与非线性迭代法相结合的方法。不但进行了理论上的详细推导,而且通过实例进行了验证,结果很好。本文提出的方法原理通俗易懂,计算过程简单,易于实行,成本低,具有重要实际意义。 相似文献
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判定地下水二维水动力弥散参数的直线图解法 总被引:1,自引:0,他引:1
弥散参数的求得,是正确认识地下水污染运移及对其控制的前提。本文根据极值理论和非线性方程线性化手段,导出了浓度和时间变化的线性关系,得出了确定弥散参数的直线图解法。它可以弥补其它方法的不足。借用实际弥散试验资料对其进行了检验,表明所建数学模型与实际模型之间吻合良好,即所求得的参数结果可信。 相似文献
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多孔介质水动力弥散尺度效应研究:现状与展望 总被引:6,自引:0,他引:6
黄康乐 《水文地质工程地质》1991,18(3):25-26,31
随着工农业生产的发展,工业“三废”大量排放、农药和化肥大面积施用、核能利用带来核废料日益增多、人口增长和都市化带来的垃圾、污水不断增加,这些污染物向地下入渗,使地下水水质遭受严重的污染或面临污染的威胁。另一方面,由于不合理开采和过量抽取地下水资源,改变了水力状态,加速了地下水污染的进程;不科学的灌溉方式引起土壤大面积的盐碱化。这些问题的日趋严重,已引起人们的高度重视。地下水污染和土壤盐碱化实质上是可溶性污染物 相似文献
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郭东屏 《西安地质学院学报》1995,17(3):64-71
对流-弥散方程和渗流基本微分方程中的源汇项,分别是决定含水层中任一内点上水质量和溶质质量时变率的重要因素之一。而关于源汇项不适当的乃至是错误的表述,在文献中却不乏其见,其影响之在是显而易见的。本文深入分析了某些表述的不当或错误之处,给出了正确的处理与表述方法。 相似文献
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应用液液萃取、固相萃取柱、固相萃取盘等传统和现代富集技术,对半挥发性有机物进行提取,建立了气相色谱-负化学电离质谱测定地下水中毒杀芬的方法。对性能较好的自制GDX-502固相萃取柱进行了条件优化。结果表明,使用填制的GDX-502固相萃取柱富集地下水中的毒杀芬,基体加标回收率为92.3%~98.5%,优于商品固相苯取柱LC-C18、ENVITM-C18以及固相萃取盘(92.8%~96.8%)和液液萃取(80.3%~88.5%);GDX-502固相萃取柱富集速度低于固相萃取盘,但远高于LC-C18和ENVITM-C18;GDX-502固相萃取柱的批量处理样品能力(12个)高于固相萃取盘(6个);同时所使用的有机试剂量远低于液液萃取。GDX-502固相萃取柱的萃取效率、分析通量、经济性和环保性具有更大的优势。 相似文献
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Galerkin有限元在处理含第二类边界条件的对流弥散方程时,针对对流项和弥散项有两种不同的格林积分变换,所得数值结果的精度也不同。一种方法是把对流和弥散项整体考虑实施格林积分转换(降低微分阶数,由二阶降成一阶),应用边界条件,得出变分方程;另一种处理方法是只对弥散项实施积分变换,应用边界条件,得出变分方程。以一维问题为参考,对两种方法的数值结果与解析解进行比较分析。 相似文献
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针对半无限长多孔介质柱体,一端为定浓度边界的水动力弥散反求参数问题,先用数值方法求解补余误差函数erfc(x)的反函数,再根据该问题的解析解,通过变量代换,构造一个基于解析解的最小二乘模型来反求水动力弥散系数。最后将该方法应用于一个实例,计算结果表明该方法比erfc(x)近似公式法、配线法、正态分布函数法等传统方法要好。 相似文献
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The Chalk aquifer of Champagne (France) baseline geochemistry has been determined using a solid solution approach for the modelling of calcite dissolution. The water–rock interactions are modelled by the speciation code CHESS from field data and Ca, Mg and Sr aqueous concentrations in groundwater. The stoichiometries of solid solutions are defined in each stratigraphic unit of the Chalk aquifer from bulk geochemistry and Chalk mineralogy of samples taken from boreholes. The initial mineralisation of water at the bottom of the unsaturated zone and the characterisation of the theoretical evolution of groundwater chemistry along the flow lines associated with incongruent calcite dissolution are calculated from this approach. 相似文献
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Francis Albarede 《Geochimica et cosmochimica acta》1976,40(6):667-673
The classical equations relating the trace element concentrations of the liquid and solid phases coexisting in the simple fractional crystallization of a parental magma have been put in a simple graphical form, which allows rapid analysis of the possible genetic relationships in a given rock suite. The effects of an incomplete separation between the two phases are taken into account. The approach does not require the use of otherwise estimated partition coefficients. Trace element data concerning the minerals of cumulates, where available, may provide an independent estimation of the effective mineral-liquid partition coefficients. With reasonable assumptions, this approach may even be applied to plutonic rocks. Interpretation of the published rare earth element data from the Southern California Batholith by this procedure suggests that a tonalitic parental magma could generate a granodioritic liquid by crystallizing 40–50 wt % of a solid residue of gabbroic composition, in agreement with Larsen's (Mem. Geol. Soc. Amer. 29, 1948) calculations. The calculated mineral-liquid partition coefficients for the REE fall in the range of published phenocryst-groundmass values for acidic volcanic rocks. 相似文献
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Integrated use of hydrochemistry and resistivity methods in groundwater contamination caused by a recently closed solid waste site 总被引:6,自引:0,他引:6
In order to investigate the groundwater contamination by solid waste disposal using both hydrochemical and geophysical methods,
the Halkalı (I˙stanbul) solid waste disposal site which was closed in 1994 was investigated. The disposal site lies on a ridge
between two valleys filled with alluvium. A total of six boreholes were drilled on two lines across the Menekşe valley adjacent
to the Halkalı site. Groundwater samples collected from these boreholes were analyzed for various contaminant parameters.
The results indicate that TDS and chloride concentrations decrease horizontally away from the waste site whereas they increase
with depth. Electrical soundings carried out at 12 locations yielded high resistivity values at the upstream part of Menekşe
valley while lower values were obtained from the locations near the leachate seepage points.
Received: 11 November 1997 · Accepted: 23 February 1998 相似文献
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在详细调查基础上,采用系统科学及水文地质分析方法,依据地形地貌、地层岩性、地质构造、示踪试验、地下水排泄基准面、喀斯特发育条件及发育规律等剖析论证流域边界,并通过钻探及示踪试验进行验证。研究结果:(1)对泸西喀斯特断陷盆地南东部的水系统边界向北移进行了修正,证实了三塘一带深部不发育的喀斯特是地下水分水岭边界,使得泸西喀斯特断陷盆地流域的径流系统和边界圈化更加准确;(2)泸西喀斯特断陷盆地流域地表水、地下水转化频繁,地表水径流特征主要以小江河在水库、河流、伏流间的径流转化过程为体现,地下水在侵溶山区接受大气降水补给后,上层径流以泉、暗河的形式在泸西盆地底面排泄后转化成地表水,最终汇集于盆地南部、通过工农隧洞及落水洞排向小江,而下层径流则以小江水面为基准,通过深层径流排泄。 相似文献
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Wayne J Walker 《Geochimica et cosmochimica acta》1974,38(10):1521-1526
The proposed methods for estimating two free energy partitioning parameters of a one site-two site model have been specifically developed for cases where data are few or inconveniently grouped and utilize pairs of values of the mole fractions of the partitioned species A in the multi-site phase (XAT) and the single site phase (XAm). Where (XAT) exceeds 0.7 the mod may become unstable such that small changes in the distribution curve gradient result in large changes in the evaluated intracrystalline exchange free energy. Such behaviour is exemplified by data from the system olivine-orthopyroxene. 相似文献
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《Geochimica et cosmochimica acta》1986,50(8):1633-1641
An experimental arrangement suitable for application of high temperature calorimetry to liquid sulfide systems has been developed. Using this approach, we have measured the integral enthalpies of mixing of Ni + NiS at 1100 K to form liquid alloys with compositions from XNis = 0.576 to XNis = 0.754. Partial enthalpies of the two components also were measured. After correcting for the enthalpies of fusion of Ni and NiS at 1100 K, the results of all measurements can be represented by an analytical expression which reflects subregular behavior of the mixing enthalpies ΔHmixl−1 = XNis2XNiA + XNisXNiS2B with A = −97.712 kJ mol−1 and B = −4.772 kJ mol−1.The standard enthalpies of formation of the high and low temperature forms of NiS were evaluated from the calorimetrically measured enthalpy change associated with the reaction between nickel and sulfur at 1021 K. The standard enthalpies of formation of Ni3S2 (heazlewoodite), Ni7S6 and Ni0.958S were determined from the enthalpy changes of reactions in which the compounds were formed from NiS and Ni at 873 K and 833 K. The standard enthalpy of formation of NiS2(vaesite) was obtained from the enthalpy change of the reaction of NiS2 with Ni to give NiS at 873 K. The following values are reported for the standard enthalpies of formation of the phases studied (in kJ mol−1): ΔHf,NiS(HT)0 = −88.1 ± 1.0 ΔHf, Ni0.958S0 = −93.2 ± 0.7ΔHf,Ni7S60 = −582.8 ± 5.7 ΔHf,NiS(LT)0 = −91.0 ± 1.0ΔHf,Ni3S2(LT)0 = −217.2 ± 1.6 ΔHf,NiS20 = −124.9 ± 1.0. 相似文献
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Quantifying regional groundwater flow between Continental Intercalaire and Djeffara aquifers in southern Tunisia using isotope methods 总被引:4,自引:0,他引:4
Large-scale interaction between the Continental Intercalaire and the Djeffara aquifer systems in the southeast of Tunisia
has been investigated with the aid of chemical and isotopic tracers. Two distinct groundwater types have been identified:
(1) the Continental Intercalaire groundwater characterized by elevated temperatures (50–61.4°C), low δ18O (−8.4 to−7.87) and δ2H (−67.2 to−59) values and negligible radiocarbon content, both testifying its great age dating from the late Pleistocene
period, and (2) the Djeffara groundwater with distinctly heavier isotopic composition (δ18O = −8.31 to −5.80, δ2H = −65.9 to −31.9). The Djeffara groundwaters reveal a distinct changes of physico-chemical and isotopic parameters near
El Hamma Faults in the northwestern part of the Djeffara basin. These changes could possibly be explained by a vertical leakage
from the Continental Intercalaire aquifer through El Hamma Faults. The mixing proportions inferred from stable isotope mass
balance prove that the contribution of the Continental Intercalaire to the recharge of Djeffara aquifer is very significant
and may reach 100% in the El Hamma region and in the northern part of Gabes. Isotope tracers strongly suggest that recent
recharge to the Djeffara aquifer system is very limited. Its current yield, particularly in its central and northern parts
can be maintained only thanks to large-scale underground inflow from the Continental Intercalaire aquifer system, which carries
late Pleistocene palaeowater. Consequently, current exploitation of groundwater resources of the Djeffara aquifer has non-sustainable
character. 相似文献
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新围涂区土壤脱盐与地下水淡化预测分析 总被引:1,自引:0,他引:1
以浙江玉环县漩门二期水库蓄淡工程背景,从土壤盐分统计预报的基本方法——数理统计法出发来预测涂区土壤的脱盐速度,建立了对数函数数学模型并进行了模型的检验与讨论,得出适用于该滩涂湿地涂区的土壤脱盐量公式并进行了预测计算。在此基础上,采用相类似的对数函数拟合的方法对涂区土壤浅层地下水淡化速度进行了预测分析。 相似文献