TDR기법을 이용한 사면전단거동 측정을 위한 연구
A Study for Slope Shear Behavior Measurement Using TDR Method
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초록
본 논문에서는 동축케이블과 TDR(Time Domain Reflectometry : 시간영역반사법) 기법을 이용하여 실내실험을 통하여 전단변위에 따른 반사 신호의 변화를 분석하여 전단변위와 반사 신호의 상관관계를 도출하였으며, 크림프(crimp) 실험을 통하여 크림프의 깊이에 따른 동축케이블 길이와 반사 신호의 상관관계를 도출하였다. 전단변위에 따라 반사 신호의 변화가 가장 큰 지점의 값에 대한 회귀 분석을 실시한 결과 전단변위에 대한 반사 신호가 2차 다항식의 관계를 가짐을 알 수 있었다. 또한 크림프 깊이에 따른 케이블 길이와 반사 신호와의 상관관계는 선형적인 관계를 나타내고 있으며, 크림프의 깊이가 커질수록 케이블의 길이에 대한 반사 신호의 감소폭이 증가함을 알 수 있었는데, 이는 크림프를 지나는 동안 펄스 에너지의 손실이 증가한다는 것을 나타내며, 크림프의 깊이가 깊을수록 펄스 에너지의 손실이 더 증가한다는 연구결과를 도출할 수 있었다.
Abstract
TDR(Time Domain Reflectometry) is a method of locating the depth to a shear plane or zone in a landslide. TDR uses an electronic voltage pulse that is reflected like radar from a damaged location in a coaxial cable. To monitor slope movement, coaxial cables are grouted in boreholes and interrogated using a cable tester. Characteristic cable signatures can be stored and compared over time for changes, indicating slope movement. In this study, there were conducted two types experiments for analysis of TDR signal. The first type is shear experiment which is obtain relationship of shear displacements and TDR signals. The other one is crimp experiment which is obtain relationship of coaxial cable crimp depth and TDR signals. As the results, it is found that relationship of shear displacements and the TDR signals is polynomial. Also coaxial cable crimp depth and TDR signals were linearly decreasing as the coaxial cable is increasing. And growing the deep of crimp, Increase decline rate of reflection signal is increasing by coaxial cable length. Because loss is growing by the pulse energy.
참고문헌 (6)
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