基于含水层非均质性随机特征的地下水脆弱性评价
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摘要
由于地质条件的复杂性,人们所能获取的地质和水文地质资料是有限的,这就导致对水文地质条件的认识具有不确定性,其中以含水层非均质特征最为显著,这对地下水脆弱性评价显然会产生显著的影响。考虑含水层的非均质特性,提出具有非平稳随机场空间相关性的地下水脆弱性评价方法。以南京市江宁区中部地区为例,用改进的连续随机增加方法(Successive Random Additional method,简称SRA)生成了渗透系数对数(lnK),具有分维Levy运动统计特征的随机场,模拟含水层渗透系数可能的非均质空间分布,采用DRASTIC方法进行地下水脆弱性评价。结果表明由此方法生成的渗透系数场变化的程度相对传统的普通克里金方法更加剧烈,更加符合复杂分布的非平稳随机场特征,在此基础上建立的地下水脆弱性评价更加符合客观事实,丰富和发展利用随机理论解决地下水环境问题的理论和方法。
Due to the complexity of geological conditions, the geological and hydrogeological data available to the people are limited,which leads to the uncertainty in the understanding of hydrogeological conditions. Among them, the heterogeneity of aquifers is the most significant one, which would have a significant impact on the assessment of groundwater vulnerability. This paper considered the heterogeneity of aquifers and proposed a groundwater vulnerability assessment method with non-stationary randomspace spatial correlation. Taking the central area of Jiangning district in Nanjing as an example, a modified successive random additional method(SRA) was used to generate a random field with fractional Levy motion statistics for the logarithm of hydraulic conductivity(ln K),and the possible non-homogeneous spatial distribution of the hydraulic conductivity was simulated,and the DRASTIC method was used to evaluate groundwater vulnerability.The results show that the degree of change in the hydraulic conductivity field generated by SRA is more severe than that of the conventional ordinary Kriging method,and it is more in line with the characteristics of complex distributed non-stationary random fields. The groundwater vulnerability assessment established on this basis is more in line with objective facts,which enriches and develops theories and methods in using stochastic theory to solve groundwater environmental problems.
Due to the complexity of geological conditions, the geological and hydrogeological data available to the people are limited,which leads to the uncertainty in the understanding of hydrogeological conditions. Among them, the heterogeneity of aquifers is the most significant one, which would have a significant impact on the assessment of groundwater vulnerability. This paper considered the heterogeneity of aquifers and proposed a groundwater vulnerability assessment method with non-stationary randomspace spatial correlation. Taking the central area of Jiangning district in Nanjing as an example, a modified successive random additional method(SRA) was used to generate a random field with fractional Levy motion statistics for the logarithm of hydraulic conductivity(ln K),and the possible non-homogeneous spatial distribution of the hydraulic conductivity was simulated,and the DRASTIC method was used to evaluate groundwater vulnerability.The results show that the degree of change in the hydraulic conductivity field generated by SRA is more severe than that of the conventional ordinary Kriging method,and it is more in line with the characteristics of complex distributed non-stationary random fields. The groundwater vulnerability assessment established on this basis is more in line with objective facts,which enriches and develops theories and methods in using stochastic theory to solve groundwater environmental problems.
引文
[1]覃荣高,曹广祝,仵彦卿.非均质含水层中渗流与溶质运移研究进展[J].地球科学进展,2014,29(01):30-41.(TAN Ronggao,CAO Guangzhu,WU Yanqing, et al.Review of the study of groundwater flow andsolute transport in heterogeneous aquifer[J].Advances in EarthScience,2014,29(01):30-41.(in Chinese))
[2]陈彦,吴吉春.含水层渗透系数空间变异性对地下水数值模拟的影响[J].水科学进展,2005(04):482-487.(CHEN Yan, WU Jichun, etal.Effect of the spatial variability of hydraulic conductivity inaquifer on the numerical simulation of groundwater[J].Advances inWater Science,2005(04):482-487.(in Chinese))
[3]阎婷婷,吴剑锋.渗透系数的空间变异性对污染物运移的影响研究[J].水科学进展,2006(01):29-36.(YAN Tingting, WU Jianfeng, et al.Impacts of the spatial variation of hydraulic conductivity on thetransport fate of contaminant plume[J].Advances in Water Science,2006(01):29-36.(in Chinese))
[4]黄冠华.非饱和水流动态空间变异的随机分析[J].水利学报,1999(04):76-81.(HUANG Guanhua. Stochastic analysis of spatialvariability for variables of unsaturated flow[J]. Journal of HydraulicEngineering,1999(04):76-81.(in Chinese))
[5] Molz F J,Boman G K. A fractal-based stochastic interpolationscheme in subsurface hydrology[J].Water Resources Research,1993,29(11):3769-3774.
[6] Hewett T A.Fractal Distributions of Reservoir Heterogeneity andtheir Influence in Fluid Transport[A].The 61stAnnual TechnicalConference[C].Soc. of Pet.Eng.,New Orleans,U.S.,1986.
[7] Painter S.Stochastic interpolation of aquifer properties usingfractional Lévy motion[J].Water Resources Research,1996b, 32(5):1323-1332.
[8]张珍,温忠辉,鲁程鹏,等.改进的DRASTIC地下水脆弱性评价模型及应用[J].水资源保护,2014,30(06):13-18.(ZHANG Zhen,WENZhonghui,LU Chengpeng,et al.A modified DRASTIC model forassessment of groundwater vulnerability and its application[J].Water Resources Protection,2014,30(06):13-18.(in Chinese))
[9]齐世鹏.土壤饱和渗透系数计算模型对比研究[D].南京:河海大学,2015.(QI Shipeng.Comparison of Soil Saturated HydraulicConductivity Computing Models[D].Nanjing:Hohai University,2015.(in Chinese))
[10] LU S L,Molz F J,LIU H H.An efficient,three-dimensional,anisotropic,fractional Brownian motion and truncated fractionalLevy motion simulation algorithm based on successive randomadditions[J].Computers&Geosciences,2003,29(1):15-25.
[11] Fama E F, Roll R.Parameter estimates for symmetric stabledistributions[J].Journal of the American Statistical Association,1971,66(334):331-338.
[12] Mantegna R N.Fast,accurate algorithm for numerical simulation ofLevy stable stochastic processes[J].Physics Review E,1999,49(5):4677-4683.
[13]黄冠华,ZHAN Hong-bin,叶自桐.水力传导度空间变异性的分形模拟研究进展[J].水科学进展,2003(02):236-241.(HUANG Guanhua,ZHAN Hongbin, YE Zitong, et al.Review on modeling ofhydraulic conductivity with fractal theory[J]. Advances in WaterScience,2003(02):236-241.(in Chinese))
[14] Aller L,Bennett T,Lehr J H,et al.DRASTIC:a standardized systemfor evaluating groundwater pollution potential using hydrogeologicsettings[R].Washington:US EPA,1987.
[2]陈彦,吴吉春.含水层渗透系数空间变异性对地下水数值模拟的影响[J].水科学进展,2005(04):482-487.(CHEN Yan, WU Jichun, etal.Effect of the spatial variability of hydraulic conductivity inaquifer on the numerical simulation of groundwater[J].Advances inWater Science,2005(04):482-487.(in Chinese))
[3]阎婷婷,吴剑锋.渗透系数的空间变异性对污染物运移的影响研究[J].水科学进展,2006(01):29-36.(YAN Tingting, WU Jianfeng, et al.Impacts of the spatial variation of hydraulic conductivity on thetransport fate of contaminant plume[J].Advances in Water Science,2006(01):29-36.(in Chinese))
[4]黄冠华.非饱和水流动态空间变异的随机分析[J].水利学报,1999(04):76-81.(HUANG Guanhua. Stochastic analysis of spatialvariability for variables of unsaturated flow[J]. Journal of HydraulicEngineering,1999(04):76-81.(in Chinese))
[5] Molz F J,Boman G K. A fractal-based stochastic interpolationscheme in subsurface hydrology[J].Water Resources Research,1993,29(11):3769-3774.
[6] Hewett T A.Fractal Distributions of Reservoir Heterogeneity andtheir Influence in Fluid Transport[A].The 61stAnnual TechnicalConference[C].Soc. of Pet.Eng.,New Orleans,U.S.,1986.
[7] Painter S.Stochastic interpolation of aquifer properties usingfractional Lévy motion[J].Water Resources Research,1996b, 32(5):1323-1332.
[8]张珍,温忠辉,鲁程鹏,等.改进的DRASTIC地下水脆弱性评价模型及应用[J].水资源保护,2014,30(06):13-18.(ZHANG Zhen,WENZhonghui,LU Chengpeng,et al.A modified DRASTIC model forassessment of groundwater vulnerability and its application[J].Water Resources Protection,2014,30(06):13-18.(in Chinese))
[9]齐世鹏.土壤饱和渗透系数计算模型对比研究[D].南京:河海大学,2015.(QI Shipeng.Comparison of Soil Saturated HydraulicConductivity Computing Models[D].Nanjing:Hohai University,2015.(in Chinese))
[10] LU S L,Molz F J,LIU H H.An efficient,three-dimensional,anisotropic,fractional Brownian motion and truncated fractionalLevy motion simulation algorithm based on successive randomadditions[J].Computers&Geosciences,2003,29(1):15-25.
[11] Fama E F, Roll R.Parameter estimates for symmetric stabledistributions[J].Journal of the American Statistical Association,1971,66(334):331-338.
[12] Mantegna R N.Fast,accurate algorithm for numerical simulation ofLevy stable stochastic processes[J].Physics Review E,1999,49(5):4677-4683.
[13]黄冠华,ZHAN Hong-bin,叶自桐.水力传导度空间变异性的分形模拟研究进展[J].水科学进展,2003(02):236-241.(HUANG Guanhua,ZHAN Hongbin, YE Zitong, et al.Review on modeling ofhydraulic conductivity with fractal theory[J]. Advances in WaterScience,2003(02):236-241.(in Chinese))
[14] Aller L,Bennett T,Lehr J H,et al.DRASTIC:a standardized systemfor evaluating groundwater pollution potential using hydrogeologicsettings[R].Washington:US EPA,1987.