Evaluation of subsidence induced by long-lasting buildings load using InSAR technique and geotechnical data: The case study of a Freight Terminal (Tuscany, Italy)

• Published in: International journal of applied earth observation and geoinformation 2019-10, Vol.82, p.101925, Article 101925
• Main Authors: Ciampalini, Andrea, Solari, Lorenzo, Giannecchini, Roberto, Galanti, Yuri, Moretti, Sandro
• Format: Article
• Language: English
• Subjects: Compressibility; Consolidation process; Geotechnical data; InSAR data; Subsidence; Tuscany
• ISSN: 1569-8432; 1872-826X
• DOI: 10.1016/j.jag.2019.101925

•This study presents the analysis of the ground deformation measured using 26 years of satellite SAR data.•We investigated the driven factors of subsidence in a densely urbanized area.•Data retrieved by several boreholes and geotechnical investigations were used to model the building load and to validate remote sensing data.•The comparison between the consolidation curve and the time series suggests that SAR data can be used to evaluate the consolidation process. This paper shows the results of the comparison between Multi-temporal Synthetic Aperture Radar (MTInSAR) products derived from different sensors (C-band ERS 1/2, Envisat, Sentinel-1 and X-band COSMO-SkyMed) and geotechnical data to investigate the driving factors of subsidence which affect a freight terminal located along the a coastal plain of Tuscany (central Italy). MTInSAR data have been acquired in a very long period, between 1992 and 2018 and were analyzed in terms of subsidence rates and deformation time series at building scale. The obtained results show that the oldest buildings are still affected by a deformation rate close to −5 mm/yr, whereas recent buildings register rates around −40 mm/yr. Time series of deformation suggest that the deformation rates decrease over time following time-dependent trend that approximates the typical consolidation curve for compressible soils. The geotechnical and stratigraphical analysis of the subsurface data (boreholes, cone penetration tests and dilatometer tests) highlights the presence of a 15 m thick layer formed of clay characterized by poor geotechnical characteristics. The comparison among InSAR data, subsurface geological framework and geotechnical reconstruction suggests a possible evaluation of the timing of the primary and secondary consolidation processes.