도시철도 터널 시공에 따른 지표침하 모니터링을 위한 시계열 InSAR 적용성 평가

초록

Tunnel excavation in urban areas is often performed close to existing surface and underground structures, making construction-induced ground settlement an important monitoring target. Conventional ground-based instrumentation provides accurate point measurements but is limited in spatial coverage and long-term applicability in dense urban environments. This study evaluates the applicability of time-series interferometric synthetic aperture radar (InSAR) as a complementary monitoring approach for urban railway tunnelling. A conventional PS-InSAR analysis was first used to select stable reference ground control points; PS-InSAR with adaptive filtering was then compared with field settlement measurements, and SBAS-InSAR was applied to examine area-wide deformation patterns in non-instrumented sections. The InSAR results reproduced the overall magnitude and temporal tendency of measured settlement at five representative locations, while the SBAS-InSAR results revealed spatially asymmetric settlement troughs and migration of the maximum settlement location along the tunnel alignment. The results indicate that time-series InSAR can complement spatially limited field instrumentation by providing additional information on the spatiotemporal distribution of surface deformation. The limitations associated with single-orbit LOS-to-vertical conversion and the lack of direct field validation for SBAS-InSAR should, however,be considered when interpreting the quantitative results.

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