Railway deformation detected by DInSAR over active sinkholes in the Ebro Valley evaporite karst, Spain

J P Galve,F Gutiérrez,C Castañeda

doi:10.5194/nhess-15-2439-2015

Abstract

Abstract. Subsidence was measured for the first time on railway tracks in the central sector of Ebro Valley (NE Spain) using Differential Synthetic Aperture Radar Interferometry (DInSAR) techniques. This area is affected by evaporite karst and the analysed railway corridors traverse active sinkholes that produce deformations in these infrastructures. One of the railway tracks affected by slight settlements is the Madrid–Barcelona high-speed line, a form of transport infrastructure highly vulnerable to ground deformation processes. Our analysis based on DInSAR measurements and geomorphological surveys indicates that this line shows dissolution-induced subsidence and compaction of anthropogenic deposits (infills and embankments). Significant sinkhole-related subsidence was also measured by DInSAR techniques on the Castejón–Zaragoza conventional railway line. This study demonstrates that DInSAR velocity maps, coupled with detailed geomorphological surveys, may help in the identification of the railway track sections that are affected by active subsidence.

Highlights

Human infrastructures located in karst environments may be affected by severe ground instability problems (Waltham et al, 2005; Gutiérrez et al, 2014)
This study demonstrates that Differential Synthetic Aperture Radar Interferometry (DInSAR) velocity maps, coupled with detailed geomorphological surveys, may help in the identification of the railway track sections that are affected by active subsidence
DInSAR techniques allowed the detection of previously unknown settlement in several stretches of two major railway lines of NE Spain

Summary

Introduction

Human infrastructures located in karst environments may be affected by severe ground instability problems (Waltham et al, 2005; Gutiérrez et al, 2014). Most of the reported Interferometric Synthetic Aperture Radar (InSAR) applications to the monitoring of high-speed railways (HSR) have been developed in China and Taiwan In these countries, railway and highway infrastructure are experiencing rapid development and they traverse numerous areas affected by ground instability phenomena (Ge et al, 2008, 2009; Hung et al, 2010; Shi et al, 2010; Tan et al, 2010; Wu et al, 2010; Zhang et al, 2010; Chen et al, 2012; Ge et al, 2013). The other stretch with active subsidence includes a 4000 m long section of the conventional Castejón–Zaragoza railway (Fig. 1) Both railway corridors traverse large sinkholes previously documented in geomorphological maps (Simón et al, 1998, 2003; Galve et al, 2009).

SAR data and processing methods

Railway deformation detected by DInSAR and interpretation

Discussion

Conclusions and final considerations