Abstract

Soil movement may be induced by a wide variety of natural and anthropogenic causes, which are detectable in the local scale, but may influence the movement of the soil over vast geographical expanses. Space borne interferometric synthetic aperture radar (InSAR) measurements of ground movement provide a method for the remote sensing of soil settlement and uplift over wide geographic areas. Based on this settlement and uplift evaluation, the assessment of the potential damage to architectural heritage structures is possible. In this paper an interdisciplinary monitoring and analysis method is presented that processes satellite, cadastral, patrimonial and building geometry data, used for the calculation of settlement and uplift damage to architectural heritage structures in Belgium. It uses processed InSAR data for the determination of the soil movement profile around each case study, of which the typology is determined from patrimonial information databases and the geometry is calculated from digital elevation models. The impact on the historic structures is calculated from the determined soil movement profile based on various soilstructure interaction models for buildings. The resulting damage is presented in terms of a numerical index illustrating its severity according to different criteria. In this way the potential soil movement damage is quantified in a large number of buildings in an easily interpretable and user-friendly fashion. The processing of InSAR data collected over the previous 3 decades allows the determination of the progress of settlement- and uplift-induced damage in this time period. With the integration of newly acquired and more accurate data, the methodology will continue to produce results in the coming years, both for the evaluation of soil settlement and uplift in Belgium as for introducing related damage risk data for existing architectural heritage buildings. Results of the analysis chain are presented in terms of potential current damage for selected areas and buildings.

Abstract

The construction of a permanent bridge required a temporary bridge parallel to the permanent bridge alignment. Preloading of the permanent bridge abutment occurred under a separate early earthworks contract. That fill was removed, and the temporary structure was constructed. The fill was then replaced behind the abutment. Movement of the southern abutment of the permanent bridge was identified but with a gap of several weeks in survey monitoring due to a XMAS break period. The abutment had moved towards the river and temporary bridge. Potential causes for movement were investigated by additional investigation adjacent to and far away from the temporary bridge piles. Post movement tests carried out included: Dilatometer Testing (DMT) to assess for shear zones (if any) for slope instability, Cone Penetration Testing (CPTu) to assess strength changes (if any) to proximity of piles and new inclinometer readings. INSAR data was also obtained. A 3-D finite element analysis (FEA) carried out by a consultant matched the measured lateral displacements at the adjacent bridge. Based on that correlation, it was concluded that the removal of the close-ended temporary piles was the main cause of the excessive movement, and this initiated a contractual claim. Correlation is not causation. This case study provides a background on the site data and numerical analysis. The FEA did not include much of the site observational and site data post movement. Given the FEA was given the same credence as the site data, this suggests that data is now considered a point of view.

Abstract

One of the challenges in urban tunnelling projects is to guarantee that the infrastructure assets crossing or adjacent to the tunnel alignment and other new build elements are not affected by the construction activity. Radar Satellite Interferometry (InSAR) is a non-invasive surveying technique which provides millimetric deformation measurements of terrain structures over wide areas without any need to access site. This technique allows a comprehensive and periodic vision, with the same accuracy as manual levelling in cities for a fraction of the cost of traditional systems. ATLAS is the Sixense’s InSAR processing chain, aimed to monitor the different tunnelling activities phases: access shaft excavation, tunnel construction and settlement. This study focuses on real data obtained by Sixense during the monitoring of urban tunnel construction work in three major projects in London (UK) and Porto (Portugal), using a combination of technologies: InSAR for remote monitoring and two topographic instrumentation methods: Topographic Control Prisms through measurements with Robotic Total Station and Topographic Levelling. The methodology employed integrated InSAR to obtain surface deformation data across the tunnel influence zone and on-site instrumentation for detailed and precise measurements. Its implementation enabled continuous monitoring, revealing accurate and real-time deformation patterns near the tunnels. The results demonstrated a significant correlation between InSAR data and on-site measurements, validating the effectiveness of this combination.

Abstract

A combined ground-based slope stability radar (SSR) and satellite-based (InSAR) monitoring system was trialled at a remote mine site in the Northern Hemisphere in order to investigate relative changes in displacement experienced by a mine waste storage facility. The relative changes in displacements along the InSAR line-of-sight (LoS) were compared to the relative changes in displacement provided by the ground-based SSR LoS. Although the two LoS are different, this study showed good agreement between the magnitude of relative displacements observed by both remote sensing technologies on the slope of the facility. Additionally, the study looked at the effectiveness of InSAR and SSR on capturing relatively shallow operational works undertaken on the tailings storage facility slope. Results showed that SSR is able to provide near real-time information about progressive trends in displacements and alert mine site personnel of potential areas that might need attention. InSAR could detect anomalies in surface deformations during the period when SSR did, but the radar signal was sufficiently low to not unequivocally attribute these responses to real surface deformations