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2026 Vol.42, Issue 4 Preview Page
Analysis of Precursory Surface Displacement Characteristics for Sewer Pipe Damage-Induced Urban Sinkholes Using CWT-SBAS-InSAR

CWT-SBAS-InSAR를 이용한 도심지 하수관 손상 싱크홀의 지표 변위 전조 특성 분석

Yu-Bin Kim1
,
Byeong-hun Song2
,
Tae-yong Park3
,
Lang Fu4
,
Hyeong-joon Seo5*
김 유빈1
,
송 병훈2
,
박 태용3
,
랑 푸4
,
서 형준5*
1Member, Undergraduate Student, Dept. of Civil Engineering, Seoul National University of Science and Technology
2Undergraduate Student, Dept. of Civil Engineering, Seoul National University of Science and Technology
3Member, MSc Student, Dept. of Civil Engineering, Seoul National University of Science and Technology
4PhD Student, Dept. of Civil Engineering and Industrial Design, Liverpool Univ.
5Member, Associate Prof., Dept. of Civil Engineering, Seoul National University of Science and Technology
1학생회원, 서울과학기술대학교 건설시스템공학과 학부과정
2비회원, 서울과학기술대학교 건설시스템공학과 학부과정
3정회원, 서울과학기술대학교 건설시스템공학과 석사과정
4비회원, University of Liverpool Department of Civil Engineering and Industrial Design 박사과정
5정회원, 서울과학기술대학교 건설시스템공학과 부교수
*Corresponding Author
31 August 2026. pp. 51-64
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Abstract

Sinkholes form when expanding subsurface voids leave the overlying ground unable to support applied loads, causing sudden surface collapse. Urban sinkholes are often associated with anthropogenic factors, such as deteriorated buried pipelines, excavation works, and inadequate backfilling. In particular, sewer pipe damage can trigger subsurface soil loss and progressive void growth beneath roads. In this study, a method combining small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) displacement time series with continuous wavelet transform (CWT), termed CWT-SBAS-InSAR, was applied to actual sinkhole cases in Seoul to analyze the time-frequency characteristics of precollapse surface displacement. The analysis revealed that precursory signals, which are not clearly discernible in conventional time-series data, manifested as concentrated energy patterns at specific temporal instances and frequency bands in the CWT spectrum. Notably, cases attributed to sewer pipe damage exhibited multiscale energy concentrations in both short- and medium-period bands, demonstrating that progressive soil loss and void growth can be expressed as time-frequency signatures. These findings suggest that CWT-SBAS-InSAR analysis may serve as a supplementary tool to support the early detection of urban sinkholes and the identification of high-risk zones.

Keywords
Continuous wavelet transform
CWT-SBAS-InSAR
SBAS-InSAR
Sewer pipe damage
Surface displacement
Urban sinkhole

싱크홀은 지표면 하부의 공동이 확장됨에 따라 상부 지반이 하중을 지지하지 못하여 붕괴되는 현상이다. 도심지 싱크홀은 노후 매설관, 굴착공사, 되메우기 등 인위적 요인과 밀접하게 연관되며, 이 중에서도 하수관 손상은 도로 하부의 토사 유실과 지중 공동 성장을 유발한다는 점에서 대표적인 원인으로 꼽힌다. 본 연구에서는 서울시 실제 싱크홀 사례를 대상으로 SBAS-InSAR 시계열 변위와 연속웨이블릿변환(CWT)을 결합한 CWT-SBAS-InSAR 기법을 이용하여 싱크홀 발생 전 지표 변위의 시간-주파수 특성을 분석하였다. 분석 결과, 일반적인 시계열에서는 명확히 구분되지 않는 싱크홀 발생 전조 신호가 CWT 스펙트럼 상에서 특정 시점과 주기 대역의 에너지 집중 패턴으로 나타났다. 특히 하수관 손상 사례에서는 단주기 및 중주기 대역에 걸친 에너지 집중 양상이 관찰되어, 점진적 토사 유실과 공동 성장 과정이 시간-주파수 신호로 표현될 수 있음을 확인하였다. 본 연구 결과는 CWT-SBAS-InSAR 분석이 도심지 싱크홀 조기 탐지와 위험 구간 선별을 위한 보조적 도구로 활용될 수 있음을 시사한다.

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Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 42
  • No :4
  • Pages :51-64
  • Received Date : 2026-06-08
  • Revised Date : 2026-08-06
  • Accepted Date : 2026-08-06
  • DOI :https://doi.org/10.7843/kgs.2026.42.4.51
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