| Title |
Pseudo-DC Resistivity Survey for Site Investigation at Urban Areas with Ambient Electrical Noises |
| Keywords |
urban site;resistivity survey;CapSASW;NDT;site investigation;도심지 지반;전기비저항 탐사;비파괴 시험;지반조사 |
| Abstract |
Recently, urban retrofit and extension, development of new buildings and facilities, and construction of underground structures like subway tunnels in urban areas give rise to significance of site investigation at urban areas. However, ambient electric noises, traffic vibrations, embedded objects work as obstacles to high-quality and accuracy in site investigation at urban areas. In this paper, a new technique called the pseudo-DC resistivity survey (in brief, PDC-R) was proposed to minimize the adverse effect of ambient electrical noises in resistivity survey. PDC-R technique utilizes an AC current with frequency range of 0.1 to 1.0 ㎐ rather than DC current, which is used for conventional resistivity survey. The motivation of using low-frequency AC current is to avoid 60-㎐ components or its multiples in the resistivity survey which ambient noises are mostly composed of. The implementation of PDC-R technique also included the parametric study on skin effect, frequency effect and current-level effect, which led to the determination of optimal values of frequency and current level for PDC-R survey. The reliability and feasibility of PDC-R technique was verified through field tests, accompanied by the comparison with DC resistivity survey and CapSASW tests. |