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|Title: ||交互應用各式地球物理探勘方法於土壤及地下水污染場址之研究;Study on the application of integrating ERT, GPR, EM methods onto soil and groundwater contaminated sites|
|Issue Date: ||2016-10-13 13:22:42 (UTC+8)|
二、地表地電阻影像法不同電極排列之解析能力及受雜訊干擾影響程度不同。為取得較高解析度的成果，建議在土壤及地下水問題調查時，電極間距應小於3 m，且測線長度應超過目標測深4 ~ 5倍以上，同時應以兩種以上的排列調查成果綜合研判。跨孔式地電阻影像法則須依據場址現況設計並反覆調整排列法，應用在地下水污染場址時，井內電極建議應以小於1 m，時間序列分析時應特須特別維持資料品質與一致性。
;Geophysical exploration methods are used to assist to assess the soil and groundwater contaminated sites, and they have not only been often used to survey the pollution distribution and hydrogeological investigation in pre-remediation, but also extended their applications into the during and post remediation analyses. However, there are limitations and bottlenecks subject to different sites, techniques and equipment. Geophysical methods results should not be randomly and arbitrarily interpreted without sufficient professionalism and detailed planning. Instead a comprehensive understand of the environment and pollutant characteristics of sites before the investigation is a must. Carefully map the properties and the qualities of the contaminated sites to the features of each technology, and then prudently hand-picked out the appropriate technology/ies to evacuate the remediation. At the same time, in order to obtain valid results, all the way from the pre-remediation investigation to the post-remediation evaluation, it is curtail to closely work with professionals from other areas such as from environmental engineering, geology, groundwater, civil engineering, biochemistry and so forth.
By numerical simulation and real case analysis, this present study explores the appropriate timing and manner of applying ERT，GPR，EM interactively onto various types of soil and groundwater contaminated sites, and what problems can be best resolved by using what kind of configuration. Therefore, the value and correctness of geophysical methods in solving the soil and groundwater contamination can be enhanced, and the application level of the methods can be promoted. The actual results of this study are:
First, to propose the best timing of applying each technology, the processes, and the pollution interpretation logic for sites with buried disposal, and factories. In general, solid wastes, and pure organic solvents are with high resistivity, and strong reflection signals often show in GPR, while heavy-metal sludge is with high electrical conductivity properties, and often cause signal attenuations in GPR.
However, underground contamination involves complex phenomena, when the hearthstone is moist, the resistivity drops, where there are biochemicals, oil products can change in electrical properties, and reactions of other pollutants can be concealed by sewage.
Second, in different ERT electrode arrangements, the degree of influence by noise interference varies. Therefore, to achieve higher resolution results, it is suggested that when investigating the soil and groundwater, the electrode spacing be less than 3 m, the survey lines be 4 to 5 times longer than the target sounding, and two or more configurations be arranged for comprehensive judgments. Cross-hole resistivity imaging needs to be designed in accordance with the features of the site, and repeatedly rearrange the setting. For example, at groundwater contaminated sites, in-well ERT electrodes should be less than 1 m, while it is important to specially maintain the data quality and the consistency when applying time-lapse analysis.
Third, an improved array, the cross-hole resistivity imaging method is integrated effectively into the groundwater remediation plan designs. Additionally, a drug spreading evaluation system is developed by using 4D image depicting to outline the major transmission after the agent injection, and with the sampling and analysis methods to locate the formations where need to be enhanced, and according to the assessment results to plan the following remediation stage to achieve the goal of accurate remediation, and improve the groundwater remediation effectiveness.
This study including its appendix contains a total of 17 cases in Taiwan. Contaminations discussed include wastes, hearthstones, soil with heavy metals, and oil and chlorinated organic solvents. Another feature is incorporating more than one hundred of internationally published literature of research in the soil and groundwater contamination for reference. Hope this study can shad light on investigation into sites with similar compositions.
|Appears in Collections:||[地球物理研究所] 博碩士論文|
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