The Application of Self-Potential Method to Investigate a Soil and Groundwater Contaminated Site

• Main Authors: Yung-Chieh Chuang, 莊詠傑
• Other Authors: Chien-chih Chen
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/99026060470492362325

碩士 === 國立中央大學 === 地球科學學系 === 104 === 　　In this study, we have proposed the use of time-lapse SP (Self-Potential) monitoring system to investigate remediation reagents injection and rainfall effect at the soil and groundwater contaminated site, located in Yung Kang, Taiwan. We set up two mutually perpendicular survey lines to continuously record the SP data at a sampling rate of 25 Hz. By averaging 1 day hourly SP median data, we calculate the time-lapse SPT (Self-Potential Tomography) with a published code SP2DINV every day, and get the following results. First, in order to prove the SP results at the soil and groundwater contaminated site, we conduct 12 sandbox experiments to compare the detecting ability of 3 SP arrays with 2 known current source, and discuss the influence from buried metal wire. We also carry on a saline injection to demonstrate the pattern of streaming potential. And from the synthetic test, we define the sensitivity of SPTs and demonstrate the ability to detect SP. Second, by analyzing the SPTs variation from 13 to 18 October 2015 and from 23 to 25 November 2015, SP monitoring system successfully monitor the remediation reagents injection and evaluate the Apparent Groundwater Velocity. Third, making use of interpolation scheme, this study filter the rainfall effect out of the raw SP data, then show the SP response to the precipitation, and evaluate the Apparent Groundwater Velocity and Streaming Potential Coupling Coefficient. Forth, by observing the positive and negative electric potential distributions in both N-S and E-W SPTs, we determine that the regional groundwater flow direction is in NNE and infer that the forefront of contamination is at 20m. Furthermore, in the daily SPTs, there are some artificial structures at a depth of circa 10 m.