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重非水相流体（DNAPLs）的电阻率一般较高,在地下介质中与周围的地下水形成明显的电性差别。利用这一特性,非侵入式的高密度电阻率法（ERT）在探测DNAPLs污染场址中污染范围展现出一定优势。然而在实际场址的调查应用中,ERT有时无法探测到显著的高阻异常,或探测的高阻异常是由于介质的非均质性产生,从而导致对DNAPLs污染分布的误判。针对该问题,文章首先基于有效介质电阻率模型,计算了不同DNAPLs饱和度情形下的地层总电阻率值,从理论上解释了当DNAPLs污染程度较低时不存在显著高阻异常的原因。进一步构建理想ERT正演模型,探讨ERT探测DNAPLs污染的适宜性。研究结果表明:介质的非均质性（例如高阻的砾石等）对ERT探测具有很强的干扰,可造成DNAPLs分布范围的误判,因此传统静态ERT探测DNAPLs污染仅适用于均质介质或者非均质介质中DNAPLs污染程度较高的条件。对于非均质介质DNAPLs污染程度较低时,需采用基于时间域的差分反演方法屏蔽介质非均质性的影响,从而准确判定DNAPLs分布。 相似文献
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为解决辽西地区干旱缺水问题,通过卫星遥感与地面物探相结合的工作方式,研究了水文地质信息提取方法及其应用技术,并在辽西地区开展了初步应用。结果表明,卫星遥感技术不仅可以从宏观上掌握研究区地下水赋存规律,还可探测到常规方法难以发现的水文地质信息,通过卫星遥感技术可以缩小地面物探工作区的范围,该方法有效提高了地下水探测的工作效率及其准确性。此外,通过对电测深电阻率值的定量分析表明,当探测到的九佛堂组岩组电阻率介于18～22Ω·m之间时,该处富水的可能性极大,该方法可有效降低在九佛堂组中物探找水工作的难度。 相似文献
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物探方法是寻找地下水的重要勘查手段之一.在查明区域水文地质条件的基础上,本文采用音频大地电磁测深和高密度电阻率法对海南省琼中县榕木村花岗岩区深部赋水断裂破碎带的位置、深度、规模和产状特征进行了探测,结果表明:赋水断裂破碎带主要表现为"凹槽"状或"条带"状低阻异常;可以采用激电半衰时(Th)、偏离度(r)以及视电阻率(ρs)等参数进行断裂破碎带含水层位置判别.通过水文地质钻探揭露,含水层位置与物探解译结果基本一致,证明激电半衰时和偏离度以及视电阻率等参数可以较可靠地确定赋水构造的位置和深度.综合物探勘查方法为水文地质钻井孔位设计提供了有效技术支撑,可对在类似地区进行地下水探测提供参考. 相似文献
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高密度电阻率法探测海水入侵咸淡水界限初步调查研究——以莱州湾为例 总被引：1，自引：0，他引：1
本文从理论上阐述了高密度电阻率法探测海水入侵界限的可行性,对该方法在莱州湾地区实例分析表明,根据高密度电阻率法反演视电阻率断面图勾划出来的咸淡水分界线与水文地质调查结果基本吻合,说明了该方法在莱州湾地区具有较好的有效性和可行性。笔者还利用视电阻率断面图确定了咸淡水水体在平面分布情况和垂向变化情况,为查清海水入侵等环境地质问题提供可靠的基础资料。该方法在探测海水入侵方面具有简单、快速、低廉、无破坏性原位探测等特点,其应用前景可观,值得推广。 相似文献
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利用ERT数据推求非均质多孔介质渗透系数初探 总被引：2，自引：0，他引：2
高密度电阻率成像法（ERT）能通过改变间距来对不同尺度上的地质体特征进行描述，近年来广泛地应用于地质、工程等领域。本文从电流场和渗流场的相似性出发来研究电阻率和渗透系数之间的关系，简要介绍了利用ERT技术所得的电阻率数据推求渗透系数的基本原理，并利用张家港大新和塘桥两处的ERT测量数据推求出渗透系数。与两地抽水试验结果和岩性取样分析的结果分别进行对比，结果较为吻合。 相似文献
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高密度电阻率法是以人工向地下施加外电场,然后通过探测场的参数变化获得电性局部差异,从而认识被测目标的一种勘探手段.该方法可利用覆盖层与下部基岩存在的电性差异来测定覆盖层的厚度.由于其效率高、探测深和精确的地电剖面成像,已成为在水文和工程地质勘察中最有效的方法之一.这里简要阐述了高密度电阻率法发展过程、勘探原理、野外工作方法,并将该方法应用到水电站选址覆盖层厚度探测中,获得了测区部位的视电阻率二维成像图.结合测区地形地质条件、地球物理特征,通过对视电阻率二维成像图异常形态,高低阻等特征的分析,推断出了地下覆盖层厚度,为水电站选址建设提供了依据. 相似文献
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《Journal of African Earth Sciences》2011,61(5):337-345
Two geophysical techniques were integrated to map the groundwater aquifers on complex geological settings, in the crystalline basement terrain in northeast Nuba Mountains. The water flow is structurally controlled by the northwest–southeast extensional faults as one of several in-situ deformational patterns that are attributed to the collision of the Pan-African oceanic assemblage of the Nubian shield against the pre-Pan African continental crust to the west. The structural lineaments and drainage systems have been enhanced by the remote sensing technique. The geophysical techniques used are: vertical electrical soundings (VES) and electrical resistivity tomography (ERT), in addition to hydraulic conductivity measurements. These measurements were designed to overlap in order to improve the producibility of the geophysical data and to provide a better interpretation of the hydrogeological setting of the aquifer complex structure. Smooth and Block inversion schemes were attempted for the observed ERT data to study their reliability in mapping the different geometries in the complex subsurface. The VES data was conducted where ERT survey was not accessible, and inverted smoothly and merged with the ERT in the 3D resistivity grid. The hydraulic conductivity was measured for 42 water samples collected from the distributed dug wells in the study area; where extremely high saline zones were recorded and have been compared to the resistivity values in the 3D model. 相似文献
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Application of electrical resistivity tomography methods for delineation of groundwater contamination and potential zones 总被引：2，自引：0，他引：2
G. Tamma Rao V. V. S. Gurunadha Rao G. Padalu Ratnakar Dhakate V. Subrahmanya Sarma 《Arabian Journal of Geosciences》2014,7(4):1373-1384
Identification of damages/changes that are affecting the underground water quality due to the effect of anthropogenic activities is often done after environmental problems have become evident or water portability being strongly affected. Two main applications of electrical resistivity tomography (ERT) methods have been addressed covering characterization of leachate movement from a composting area of a Sugar Mill in Southern India. Good correlation has been obtained between ERT and groundwater quality assessments as well as from groundwater monitoring data sets. The study helped in conceptualization of hydrogeologic framework in basaltic terrain. Impacts on groundwater regime associated with urbanization and industrialization can easily be assessed through the variation of resistivity in the inverse resistivity pseudo-section model of the ERT investigations. Assessment of groundwater potential in an upcoming Urban Node, Greater Hyderabad city has been illustrated in the second example. Identification of good thickness of weathered regolith for location of water harvesting through Green Fingers evolved. The small infrastructure would help carrying of enhanced surface runoff as well as to sustain groundwater yield in the urban node and thereby ensuring sustainable groundwater resource exploitation. The above studies have illustrated immense potential of the ERT tools in the assessment of groundwater contamination as well as groundwater potential. 相似文献
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The western sector of the Tagliamento River basin (Friuli Venezia-Giulia Region; northern Italy) is characterized by important water resources, both superficial and underground. In particular, in the Quaternary deposits of the plain, up to a depth of 500 m, six artesian aquifer systems exist. A large amount of lithological, geomorphological, and hydrogeological data is presented, allowing for definition of (a) the principal aquifer system of the area to a depth of about 500 m; (b) geometrical characteristics of the aquifers (thickness, lateral extension, etc); (c) the hydraulic parameters (hydraulic conductivity, transmissivity); (d) chemico-physical characteristics of the water; and (e) vulnerability to pollution of the aquifer systems. In a test area, where many boreholes were drilled for fresh water supply, the conceptual hydrogeological model was integrated by a detailed and repeated three-dimensional (3D) resistivity survey using combined electrical resistivity tomography (ERT) and time-domain electromagnetic (TDEM) soundings. ERT investigation was mainly used to get detailed information about geometry and porosity of the overburden and to calibrate the shallowest TDEM information. 相似文献
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Robin E. Nimmer James L. Osiensky Andrew M. Binley Kenneth F. Sprenke Barbara C. Williams 《Hydrogeology Journal》2007,15(5):877-890
Electrical resistance tomography (ERT) was used to monitor a conductive plume dilution experiment that was conducted in fractured basalt in order to assess its applications in this type of fractured-rock environment. Tap water was injected into an injection well for 34 days to dilute a pre-existing potassium chloride (KCl) plume at a site in Idaho, USA. No further fluids were introduced artificially during a 62-day monitoring period. Both surface ERT and cross-borehole ERT were used to monitor dilution and displacement of the plume. A square grid of land-surface electrodes was used with the surface ERT. Three-dimensional images of surface ERT delineated areas of increased and decreased resistivities. Increasing resistivities are attributed to dilution/displacement of the KCl solution by tap-water invasion or the influx of seasonal recharge. Decreasing resistivities resulted from redistribution of residual KCl solution. Cross-borehole ERT was conducted between the injection well and each of seven surrounding monitoring wells. Polar plots of the injection-well resistivity data in the direction of each monitoring well delineate specific locations where tap water seeped from the injection well via preferential flow paths determined by time-dependent resistivity increases. Monitoring-well data indicate locations of clustered and isolated regions of resistivity changes. 相似文献
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Mohamed Khalil Akpofure Orubu Brad Rutherford Marvin Speece Fernando Santos Mohammad Farzamian 《Arabian Journal of Geosciences》2018,11(23):764
Geoelectrical methods involving electrical resistivity tomography (ERT), self-potential (SP), frequency domain electromagnetic (FDEM), and very low frequency (VLF) methods have been used to provide valuable information in locating a known sulfide ore body in Soap Gulch, Montana. The study develops basis of comparison for the geophysical techniques employed. Ranges of resistivity along the area have been established using interpreted ERT which can help to understand the subsurface distribution of sulfides in the area. A sulfide body was delineated from the survey area corresponding to anomalously low resistivity values on the ERT section, negative SP, and high apparent current density zone in VLF. Depth to the localized ore zone ranges approximately from 10 to 20 m. FDEM data reflect the conductivity distribution of the shallow subsurface (less than 6 m deep); hence, the delineated sulfide zone had minimal contribution to FDEM measurements. The results of the study show that SP, VLF, and ERT methods provide significant information in localizing ore bodies. The survey revealed that the resistivity values obtained from ERT profile corroborate the FDEM, SP, and VLF from the area. 相似文献
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Diesel transport monitoring in simulated unconfined aquifers using miniature resistivity arrays 总被引：2，自引：0，他引：2
The principal aim of this study is to assess the scope of monitoring diesel plume migration in a scaled aquifer model with
a miniaturised electrical resistivity array. Respectively 1000 and 500 ml of diesel were injected in both the unsaturated
and water-saturated zones of a sand body overlying a clay aquitard, and diesel migration was monitored with a miniature electrode
array and an off-the-shelf resistivity meter. Inverted time-lapse electrical resistivity tomography (ERT) data reflect downward
and lateral spreading of the diesel plume away from the injection point in the unsaturated zone. Diesel was also imaged to
spread upwards and laterally away from the injection point in the saturated zone, as controlled by capillary rise. In both
cases later-time ERT images reflected preferential pooling of diesel on the water table, as well as vertical smearing of pooled
diesel in response to simulated water-table fluctuations. Repeat fluid electrical conductivity (EC) and dissolved oxygen (DO)
measurements validate the observed changes in bulk resistivity caused by both diesel injections. Artefacts introduced by 2D
inversion of 3D contaminant transport were abound. Time-lapse ERT imaging of diesel transport is therefore inferred to be
feasible and well-suited to complementing conventional techniques of intrusive site investigation, although time-lapse 3D
or 4D ERT imaging is strongly advocated. 相似文献
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Micòl Mastrocicco Giulio Vignoli Nicolò Colombani Nasser Abu Zeid 《Environmental Earth Sciences》2010,61(2):311-322
A portion of an unconfined alluvial aquifer located in the Padana Plain (Italy) was characterized following an integrated
hydro-geophysical approach. Initially an electrical resistivity tomography (ERT) survey was employed to localize the boundaries
of a modest paleo-channel body and to design the installation of a groundwater monitoring network. Multilevel slug-tests were
performed to estimate the aquifer’s saturated hydraulic conductivities. Determined permeability values together with electrical
resistivity data were correlated. The correlation resulted in a site specific bi-logarithmic linear relationship. Based on
this relationship, punctually determined hydraulic conductivities were spatially extended over the studied flow domain. Finally,
continuously measured piezometric heads were used to calibrate a 3D flow model. Sensitivity analysis was performed to confirm
the reliability of the reconstructed permeability field, as well as, to assess the minimum number of direct measurements needed
to safely characterize the selected aquifer portion. The integration of the ERT survey results with the classical hydrogeological
tests can be conveniently applied to constrain the permeability field during flow model calibration. Although the applicability
of the determined relationship is site specific, the followed procedure is useful especially when there is a need to optimize
the available resources and in case of small-scale pilot studies. 相似文献
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F. J. Chirindja T. Dahlin N. Perttu F. Steinbruch R. Owen 《Hydrogeology Journal》2016,24(6):1583-1592
This study focusses on the hydrogeology of Urema Graben, especially possible interactions between surface water and groundwater around Lake Urema, in Gorongosa National Park (GNP). Lake Urema is the only permanent water source for wildlife inside GNP, and there are concerns that it will disappear due to interferences in surface-water/groundwater interactions as a result of changes in the hydraulic environment. As the lake is the only permanent water source, this would be a disaster for the ecosystem of the park. The sub-surface geology in Urema Graben was investigated by 20 km of electrical resistivity tomography (ERT) and three magnetic resonance sounding (MRS) surveys. The average depth penetration was 60 and 100 m, respectively. The location of the ERT lines was decided based on general rift morphology and therefore orientated perpendicular to Urema Graben, from the transitional areas of the margins of the Barue platform in the west to the Cheringoma plateau escarpments in the east. ERT and MRS both indicate a second aquifer, where Urema Lake is a window of the first upper semi-confined aquifer, while the lower aquifer is confined by a clay layer 30–40 m thick. The location and depth of this aquifer suggest that it is probably linked to the Pungwe River which could be a main source of recharge during the dry season. If a dam or any other infra-structure is constructed in Pungwe River upstream of GNP, the groundwater level will decrease which could lead to drying out of Urema Lake. 相似文献
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岩柱中水体入渗过程的高密度电阻率成像法研究 总被引：4，自引：1，他引：4
本文应用高密度电阻率成像法探讨了室内实验尺度岩柱中的这一人渗过程。首先建立了电法勘探的电位场数学模型，用有限元法进行了电位场正问题的求解。然后应用基于序列二次规划(SQP)方法的电阻率反演算法，由测量数据反演得到了岩石电阻率在二维空间上的分布。由岩柱中水体人渗过程的电法测量数据反演得到的电阻率图像反映了岩柱中水分的空间变化过程。岩柱中电阻率的空间分布及其随时间的变化表明水体的人渗是不均匀的，在岩柱周边渗流较快，而在中部存在滞后现象。得到的相对电阻率图像也反映了岩柱周边存在的微裂隙。 相似文献