Cho, Jae-Hyoung Jung, Ji-Hyun Kim, Se-Yun 2024-01-19T23:31:49Z 2024-01-19T23:31:49Z 2021-09-03 2018-02 0196-2892 https://pubs.kist.re.kr/handle/201004/121736 A cross-borehole pulse radar system was operated to detect an intrusive man-made tunnel terminated just 1.2 m away from the line of sight between a newly drilled borehole pair at a tunnel test site. Unlike conventional radar signatures on a fully penetrated air-filled tunnel, the relatively fast arrival in the measured time-of-arrival (TOA) profile was highly suppressed at the depth of the terminated tunnel. To analyze the TOA contraction at a terminated tunnel without drilling additional borehole pairs, a finite-difference time-domain (FDTD) simulator is implemented using the accurately measured location information on the terminated tunnel and borehole pair. The relation curves between the time advance in the TOA profile and the penetration length of the terminated tunnel are plotted in the high and low limits of electrical properties of background rock. To verify the accuracy of our FDTD simulated results, the wideband complex permittivity profiles of the core rock samples' boring at the tunnel test site are measured using an open-ended coaxial probe method. The calculated time advances agree well with the measured values in both cases of fully penetrated and closely terminated borehole pairs in the test site. The presented time advance curves for various penetration lengths will be a valuable guideline on detection of a terminated tunnel in site. English IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC DIPOLE ANTENNA PATTERN TIME WAVE Analysis of Cross-Borehole Pulse Radar Signatures on a Terminated Tunnel With Various Penetration Lengths Article 10.1109/TGRS.2017.2754946 1 IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, v.56, no.2, pp.799 - 807 IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 56 2 799 807 scie scopus 000424627500015 2-s2.0-85031776613 Geochemistry & Geophysics Engineering, Electrical & Electronic Remote Sensing Imaging Science & Photographic Technology Geochemistry & Geophysics Engineering Remote Sensing Imaging Science & Photographic Technology Article DIPOLE ANTENNA PATTERN TIME WAVE Borehole finite-difference time domain (FDTD) pulse radar terminated tunnel time of arrival (TOA)