Augmented satellite InSAR for assessing short-term and long-term surface deformation due to shield tunnelling

• Published in: Tunnelling and underground space technology 2021-04, Vol.110, p.103745, Article 103745
• Main Authors: Reinders, Kristina J., Hanssen, Ramon F., van Leijen, Freek J., Korff, Mandy
• Format: Article
• Language: English
• Subjects: Deformation; Evaluation; Ground deformations; InSAR; Long time series; Monitoring; Satellites; Settlement analysis; Settlements; Settling; Soil settlement; Subways; Tunnel construction; Tunneling shields; Tunnelling; Tunnels; Underground construction
• ISSN: 0886-7798; 1878-4364
• DOI: 10.1016/j.tust.2020.103745

•Generic applicability assessment of InSAR for shield tunnelling.•Use of the North/South Metro Line in Amsterdam as a case.•Evaluation of InSAR and conventional surface levelling measurements.•Introduction of an augmented implementation of InSAR.•InSAR as complementary monitoring tool to detect long-term surface deformation. In this work, we investigate if, when, and how satellite InSAR can be used for evaluating surface settlements that occur during shield tunnelling in soft soil areas. We evaluate the applicability of InSAR prior, during, and after tunnel construction. Special emphasis is placed on the influence of the InSAR phase ambiguities in relation to short-term settlements that may occur during tunnel construction. We demonstrate that a rough analytic settlement prediction can be sufficient to resolve the most probable phase ambiguity level, leading to an augmented implementation of InSAR. We use the shield tunnel of the in North/South Metro Line Amsterdam as a case study, where surface levelling data is available to assess and validate the results. We conclude that InSAR is a valuable complementary source of information as it provides data outside the area of the conventional surveying benchmarks and it reveals relevant information about settlement patterns before and after traditional construction monitoring periods.