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Continuous, Remote and Long-Term Tunneling Monitoring with InSAR INFORMATION FROM SPACE Authors: C. Giannico, A. Belson, A. Urdiroz, G. Falorni Presenter: Alessandro Ferretti tre-altamira.com | © TRE ALTAMIRA 2016 Overview » Introduction » InSAR: The Technology » Present and future trends » Applications to civil engineering and tunneling monitoring » Summary 2 About TRE ALTAMIRA » Leading providers of InSAR solutions for measuring ground motion: Offices in Barcelona, Vancouver and Milano Largest InSAR group (>75 people) Worldwide presence and operations Part of the CLS group Processing Centre specifically designed for InSAR data processing Continuous R&D and innovation activities Proprietary techniques and tools: SqueeSAR™, DespecKS™, TREmaps™ Milano team » Barcelona team Vancouver team Data center, Milano ALTAMIRA and TRE joined forces and became the largest InSAR group worldwide INSAR: THE TECHNOLOGY The secret behind interferometry: the wavelength is the “unit of length” (cm) ΔR R2 R1 time R1 ΔR Reflecting object R2 Advanced InSAR Analysis Ground Measurement Points time Multi-temporal satellite acquisitions Time-series of deformation SqueeSAR™: Information Provided A SqueeSAR™ analysis provides the following main info: • Measurement Point (PS/DS) Position [m] (lat, long, height) • Measurement Point (PS/DS) Annual Displacement Rate [mm/yr] [mm] Time series of displacement [time] • Measurement Point (PS/DS) Displacement Time-Series [mm] An example over a city: London Accuracy » Positioning EASTING NORTHING HEIGHT C-band data ±7m ±2m ± 1,5 m X-band data ±3m ±1m ± 1,5 m Precision (1) » Displacement Precision (1) LOS displacement Average displacement rate Single measurement < 1 mm/year ± 3 mm Nominal values for datasets of >40 images and for MP <4 km from REF Main market sectors 1. Oil&gas: • Environmental monitoring • Reservoir optimization • pipeline monitoring 2. Public administrations: • Landslide mapping • Natural hazards 3. Engineering companies: • Infrastructure monitoring • Route planning 4. Mining companies: • Open pit monitoring 10 NEW TRENDS Wide Area Mapping ESA SAR data >8,000 SAR scenes >20,000,000 PS Visualization technology Web-platform for fast • Visualisation • Delivery • Storage of SqueeSAR™ results New High Resolution Data TerraSAR-X Double-Geometry Analysis Ascending Descending θ θ ddesc PS dreal dasc 15 APPLICATIONS FOR CIVIL ENGINEERING InSAR Applications Civil Engineering Planning Construction − Prior to construction: ground motion analysis ante operam (based on satellite archive data) can help identify unstable areas and allows users to add another layer of information during the design phase − During construction: InSAR data can assess the impact of big construction works on the surrounding area, especially in densely populated urban areas − Post-construction phase: - Post operam monitoring of surface deformation phenomena and – in general – of possible displacements - A posteriori analyses possible thanks to satellite archives from 1992 Maintenance - quantification of possible displacements affecting the infrastructure and the surrounding areas. Radar technology measures motion before, during and after construction in order to make decisions 17 about viability and safety at every stage. Monitoring Excavation Works Railway tunnel construction Sicily, Italy Railway tunnel in urban area Sicily, Italy InSAR was used: • To gain insight about the displacement field affecting the AOI ante operam. • To get information about the spatial extent and the magnitude of surface settlement (in synergy with in situ instrumentation) Two High Resolution (HR) X-band datasets were processed to estimate both vertical and east-west horizontal displacements. Barla et al., 20016 – InSAR Monitoring of tunnel induced ground movements. Geomechanics and Tunnelling (9, 2016) 20 Time-lapse analysis » » » Time-lapse analysis of the displacement time series. Correlation between deformation and tunnel face advancement. Extent of the subsiding area and amount of lost volume calculated for each period. 01/2012 – 06/2012 06/2012 – 12/2012 Vertical Displacement 12/2012 – 06/2013 Key findings 01/2012 – 06/2014 » The area affected by significant deformation turned out to be larger than expected. » InSAR data provided a characterization of the surface deformation occurring before, during and after tunnel excavation. The integration of InSAR information with in situ data (boreholes, cross-hole) turned out to be extremely helpful to understand the reasons of an abrupt compaction phenomenon that affected some buildings (which were evacuated). » Metro lines network construction Paris, France InSAR for the Grand Paris Express Yesterday, Today and the Next 10 years 24 InSAR Grand Paris Express Project 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 High resolution historical study by section (2011-2015) The analysis of this section provides a good example of the high density of measurement points achievable wit High-Resolution X-band SAR data. InSAR monitoring activities are planned until 2025. 25 Canada Line construction Vancouver, Canada Canada Line Opened in August 2009 SINGLE BUILDING ANALYSIS Millennium Tower – San Francisco Completed in 2009, the 58-storey Millennium Tower has recently been showing signs of sinking and tilting. Although the cause has not been pinpointed, it is believed that the movements are connected to the supporting piles not firmly resting on bedrock. 29 Medium-Resolution – Sentinel-1 InSAR data http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-1/Satellites_confirm_sinking_of_San_Francisco_tower 30 High-Resolution – TerraSAR-X InSAR data 31 SUMMARY Conclusions » Thanks to its high precision and to the availability of satellite data archives covering two decades, SqueeSAR™ represents one of the most powerful technique able of detecting surface displacements. » The processing of archive satellite data allowed additional assessment of deformational behaviour ante operam (i.e. before the start of tunnelling activities), and therefore independent of any construction work » InSAR data cannot be used as a real-time monitoring tool due to the current revisiting times of the satellites (a few days), but the number of “continuous monitoring” projects is increasing steadily. » The capability of SqueeSAR™ to remotely monitor areas much wider than any traditional surveying technique (without the necessity to install anything on ground), makes InSAR data particularly suitable for complementing in situ instrumentation and define the best locations for in situ instruments. TRE TRE CANADA ALTAMIRA Ripa di Porta Ticinese, 79 20143 Milano Italy Suite #410 475 W. Georgia Street Vancouver BC V6B 4M9 Canada C/ Corsega, 381-387 E-08037 Barcelona Spain Tel: +39 02 4343 121 Fax: +39 02 4343 1230 Tel: +1 604 331 2512 Fax: +1 604 331 2513 Tel.: +34 93 183 57 50 Fax: +34 93 183 57 59 This document contains confidential proprietary information and is intended solely for the recipient. The contents of this document, including information related to TRE-ALTAMIRA INFORMATION’s methodology and know-how, may not be disclosed in whole or in part to any third party by any means or used for any other purpose without the express written permission of TRE-ALTAMIRA INFORMATION.