Application of Ground Penetrating Radar for Estimation of Loose Layer
지반 이완구간 추정을 위한 지하투과레이더의 적용

Won-Taek Hong, Seonghun Kang, Jong-Sub Lee
2015 Journal of the Korean Geotechnical Society  
An investigation of a void and a loose layer of the ground is essential in order to prevent the losses of life and properties caused by subsidence and sinkage of the ground. Recently, studies on the ground penetrating radar survey have been actively conducted in order to estimate the void and the loose layer of the ground. However, an error can be committed by contrarily predicting a dense ground and a loose layer because the ground penetrating radar estimates an interface depth between
more » ... pth between geo-materials that have different electrical impedances. In this study, a loose ground depth is estimated using the characteristics of the reflected electromagnetic wave obtained from the ground penetrating radar survey. To gather the signals according to the loose ground depths, the ground penetrating radar survey is conducted on a field which underwent a huge ground settlement. In addition, the dynamic cone penetration test is performed to verify the result of the loose ground depth estimation from the ground penetrating radar survey. From the analysis of the reflection characteristics of the electromagnetic wave, a phase of an electromagnetic wave reflected from a denser soil layer is found to be identical with that of the first measured signal. On the other hand, a phase of an electromagnetic wave reflected from the loose soil layer is found to be opposed to that of the first detected signal. The comparison between the dynamic cone penetration index and electromagnetic signals by the ground penetrating radar shows that the estimated depth of the loose or dense layer is perfectly matched with a high reliability. The ground penetrating radar survey and the signal analysis performed in this study can be used not only for the survey of interface depth between the discontinuity layers but also for the estimation of the loose layer. 요 지 대규모 지반침하 및 지반함몰로 인한 재산, 인명피해를 사전에 예방하기 위하여 지반의 공동 및 이완구간에 대한 조사는 필수적이다. 최근, 지하투과레이더를 이용한 지반침하 및 지반함몰 구간 예측과 관련된 연구가 활발히 진행되 고 있으나, 기존의 지하투과레이더 탐사에서는 전기적 임피던스가 서로 다른 층간 경계면 심도만을 산정하므로 조밀 한 지반과 느슨한 지반을 서로 반대로 예측하는 오류를 범할 수 있었다. 본 연구에서는, 지하투과레이더로부터 획득된 전자기파의 반사파 특성을 이용하여 이완구간 심도를 추정하고자 하였다. 이완구간에 따른 신호획득을 위하여 과거 침하이력이 있었던 현장을 대상으로 지하투과레이더 탐사가 수행되었으며, 결과의 상호비교 및 검증을 위하여 동적 1 정회원, 고려대학교 건축사회환경공학부 박사과정 (Member, Ph.D. Student, School of Civil, Environmental and Architectural Engrg., Korea Univ.) 2 비회원, 고려대학교 건축사회환경공학부 석사과정 (Graduate Student, School of Civil, Environmental and Architectural Engrg., Korea Univ.) 3 정회원, 고려대학교 건축사회환경공학부 교수 (Member, Prof.,
doi:10.7843/kgs.2015.31.11.41 fatcat:ggfg6qlmffbpnbvb2zg3hjbjve