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Alexandre Lisboa Lago Vagner Roberto Elis Welitom Rodrigues Borges Giovanni Chaves Penner 《Environmental Geology》2009,58(2):407-417
Geophysics has been shown to be effective in identifying areas contaminated by waste disposal, contributing to the greater efficiency of soundings programs and the installation of monitoring wells. In the study area, four trenches were constructed with a total volume of about 25,000 m3. They were almost totally filled with re-refined lubricating oil waste for approximately 25 years. No protection liners were used in the bottoms and laterals of the disposal trenches. The purpose of this work is to evaluate the potential of the resistivity and ground penetrating radar (GPR) methods in characterizing the contamination of this lubricant oil waste disposal area in Ribeirão Preto, SP, situated on the geological domain of the basalt spills of the Serra Geral Formation and the sandstones of the Botucatu Formation. Geophysical results were shown in 2D profiles. The geophysical methods used enabled the identification of geophysical anomalies, which characterized the contamination produced by the trenches filled with lubricant oil waste. Conductive anomalies (smaller than 185 Ωm) immediately below the trenches suggest the action of bacteria in the hydrocarbons, as has been observed in several sites contaminated by hydrocarbons in previously reported cases in the literature. It was also possible to define the geometry of the trenches, as evidenced by the GPR method. Direct sampling (chemical analysis of the soil and the water in the monitoring well) confirmed the contamination. In the soil analysis, low concentrations of several polycyclic aromatic hydrocarbons (PAHs) were found, mainly naphthalene and phenanthrene. In the water samples, an analysis verified contamination of the groundwater by lead (Pb). The geophysical methods used in the investigation provided an excellent tool for environmental characterization in this study of a lubricant oil waste disposal area, and could be applied in the study of similar areas. 相似文献
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本文针对水利水电工程中的混凝土构件无损探测问题,提出了一种新的反演成像方法.传统方法主要依赖人工经验观察偏移探测数据,精度无法保证.这种方法以Maxwell方程的TM问题为数学模型,在混凝土的表面放置发射源与接收器,根据探地雷达的接收数据,采用同伦优化方法结合收敛速度较快的阻尼高斯牛顿方法作为反演算法,其成像结果更具定量化和可视性.该成像方法克服了传统雷达剖面图只能近似地反映混凝土中埋藏物及缺陷的深度、大小等缺点,不仅能够探测混凝土内部异物的位置,而且能够比较准确地确定异物的大小及属性.通过计算机模拟以及对实际资料的处理,验证了该反演成像结果直观、可靠、具有一定的应用价值. 相似文献
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利用探地雷达观测分析早春融雪前后沙丘表层土壤含水量的时空分布 总被引:1,自引:0,他引:1
积雪融水是古尔班通古特沙漠春季植物发育的重要水源, 快速获取早春沙丘的土壤水分变化具有十分重要的生态学意义. 2010年3、 4月分别使用探地雷达进行了多次测量实验, 结果显示: 1)融雪初期, 沙丘顶部土壤的自由水含量最大, 阳坡次之, 且融雪水在重力作用下沿坡面侧向缓慢流动, 在坡底汇集, 主导了融雪初期乃至整个春季沙丘表层土壤水分的分布格局; 2)融雪后期, 由于阴坡积雪和冻土消融相对滞后, 表层土壤含水量略高于阳坡, 而沙丘顶部由于融雪最早且融雪期间水分转移最多而表面最为干燥; 3)通过与时域反射仪的同步测量结果对比, 探地雷达的测量精度被有效控制在0.03范围内, 且探地雷达提供的连续数据更有利于从细节上把握土壤含水量的变化趋势, 为中小尺度土壤水分的动态研究提供了一种科学、 有效的技术手段. 相似文献
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为解决国内日益增长的地质雷达需求和目前国内所用雷达绝大部分都是国外进口的矛盾,作者同国内专家共同研发国产地质雷达.本文根据实际工作中的需求,探讨了地质雷达硬件和软件研发设计中的几个细节问题,使得生产出来的地质雷达能够更优质、高效的为生产服务. 相似文献
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This paper proposes a new method of integrated system calibration that uses the transmitting and receiving signals from the impulse ground penetrating radar itself. In order to eliminate the influence from each subsystem or part including antenna, transmitter, receiver, signal processing circuits and transmission cables, two new calibration parameters that are different from the conventional S-parameters are introduced. The characteristic and influence of all parts in the transmitting and receiving channels are incorporated into the calibration equation through the new parameters. The calibration results of the radar detection data show that the new integrated system calibration can improve the quality of the data greatly in many aspects. It removes direct coupled waves, suppresses wave distortion and tail oscillation, and improves the quality of waveform and signal-clutter-ratios. It also compresses the pulse width and enhances resolution. 相似文献
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Most ground-penetrating radar (GPR) measurements are performed on nearly flat areas. If strongly dipping reflections and/or diffractions are present in the GPR data, a classical migration-processing step is needed in order to determine the geometries of shallow structures. Nevertheless, a standard migration routine is not suitable for GPR data collected on areas showing a variable and large topographic relief. To take into account topographic variations, the GPR data are, in general, corrected by applying static shifts instead of using an appropriate topographic migration that would place the reflectors at their correct locations with the right dip angle. In this article, we present an overview of Kirchhoff's migration and show the importance of topographic migration in the case where the depth of the target structures is of the same order as the relief variations. Examples of synthetic and real GPR data are shown to illustrate the efficiency of the topographic migration. 相似文献