| Summary: | 碩士 === 健行科技大學 === 土木工程系空間資訊與防災科技碩士班 === 103 === n Electrical Resistivity Tomography (ERT) survey, different electrode arrays would affect the resolution, sensitivity and the imaging ability may be affected by the lateral 3D effect. This study is to study five electrode configuration applied in groundwater contaminated site in Taiwan, including Wenner-Schlumberger, Pole-Pole, Dipole-Diploe, Pole-Diploe and Edge-Gradient array, to evaluate their advantages and disadvantages. First, use numerical simulation with the same model and algorithm to compare the resolution with the above-mentioned electrode arrays. Second, compare the tomography in the field site with different measurement-parameter such as the interval between two electrodes and the measure time. In the last, apply the investigation results to a soil and groundwater pollution gas station site. In this study, we total simulate two differential models and test four types of electrode intervals in the field site. In the field site, we collected 63 ERT data. And in the pollution site, we conducted 6 survey lines to get 2D electrical resistivity tomography, and one 3D electrical resistivity image data.
From numerical simulation, field site investigation and contaminated site research, we found that (1) Wenner - Schlumberger has better quality of data. (2) Wenner - Schlumberger and Edge-Gradient have higher resolution than others. (3) Dipole-Diploe and Edge-Gradient are easier affected by lateral 3D effect, but their resolutions to high resistivity anomaly are better. (4) Pole-Pole has poor resolution, but its lateral 3D effect is the smallest, and its sounding depth is the deepest.
According to this research results, we suggested that it is better to use Wenner - Schlumberger and Edge-Gradient array to the soil and groundwater contaminated site. If it is in the high noises field site or it needs to do deeper sounding, it could append Pole-Pole array.
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