Detection and Monitoring of Tunneling Induced Ground Movements Using Sentinel-1 SAR Interferometry

Matteo Roccheggiani,Emanuela Tirincanti,Daniela Piacentini,Daniele Perissin,Marco Menichetti

doi:10.3390/rs11060639

Matteo Roccheggiani, Emanuela Tirincanti + Show 3 more

Open Access

https://doi.org/10.3390/rs11060639

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Journal: Remote sensing	Publication Date: Mar 15, 2019
Citations: 39	License type: CC BY 4.0

Affiliation: University of Urbino

Abstract

SAR interferometry is a powerful tool to obtain millimeter accuracy measurements of surface displacements. The Sentinel-1 satellite mission nowadays provides extensive spatial coverage, regular acquisitions and open availability. In this paper, we present an MT-InSAR analysis showing the spatial and temporal evolution of ground displacements arising from the construction of a 3.71 km overflow tunnel in Genoa, Italy. Underground tunneling can often modify the hydrological regime around an excavated area and might induce generalized surface subsidence phenomena due to pore pressure variations, especially under buildings. The tunnel was excavated beneath a densely urbanized area lying on upper Cretaceous marly limestone and Pliocene clays. Significant cumulative displacements up to 30 mm in the Line of Sight (LOS) direction were detected during the tunnel excavation. No displacements were recorded before until the middle of 2016. The Persistent Scatterers Interferometry (PSI) analysis reveals in high detail the areal subsidence, especially where the subsurface is characterized by clay and alluvial deposits as well as there is the presence of large building complexes. The time-series and the displacement rate cross-sections highlight a clear relation with the tunnel face advancement, responsible for the subsidence phenomena, which proceeded northward starting from the middle of 2016 to the end of 2017. The stabilization occurred in a range of five-six months from the beginning of each displacement phase. Due to the low subsidence ratio the ground settlements did not cause severe damages to the buildings.

Highlights

Genoa is a historic city and seaport of northern Italy with almost 600,000 inhabitants, capital of the Liguria region (Figure 1)
In November 2011, a devastating flood hard-hit especially the areas arranged along the Fereggiano river. This event led to the loss of some human lives. To quickly put these areas in hydraulic safety, the municipality and the Genoa competent authorities found the solution in the construction of a drainage tunnel, extending a 909 m long track already partially built in the ‘90s but never completed (Figure 1)
In this work we used the procedures implemented in SARPROZ software [32] adopting a classic persistent scatterers interferometry (PSI)

Summary

Introduction

Genoa is a historic city and seaport of northern Italy with almost 600,000 inhabitants, capital of the Liguria region (Figure 1). The hydraulic setting of the Bisagno river and his tributary Fereggiano (Figure 1), appears completely inadequate for flood events, especially in the light of the modified rainfall regime due to recent climate change. This river originates at 675 m a.s.l., and has a catchment extending over an area of 95 km2 It crosses the Genoa city center after 25 km, entering a covered section for the last 1.4 km before flowing into the Ligurian sea. This event led to the loss of some human lives To quickly put these areas in hydraulic safety, the municipality and the Genoa competent authorities found the solution in the construction of a drainage tunnel, extending a 909 m long track already partially built in the ‘90s but never completed (Figure 1).

Area of Interest and Geological Setting

Dataset and Methodology

Results and Discussion

Conclusions