Satellite InSAR Monitoring In Tunnelling Projects

Abstract

Satellite radar interferometry (InSAR) has been widely applied during all phases (design, construction, and operation) of tunneling projects for monitoring ground deformation in both urban and nonurban areas. In urban contexts, which are particularly sensitive to any ground deformation associated with tunneling activities, InSAR significantly improves the quality of any monitoring program by refining in situ observations. The high density of "natural targets" or measurement points obtained with SqueeSAR processing means there is no need for installation of ground-based instruments. Wide-area coverage provides a synoptic view that extends well beyond the immediate surroundings of the tunnel, where most in situ instrumentation is concentrated. This helps identify and monitor unexpected deformation (e.g. from dewatering) away from the tunnel alignment during the construction phase, or residual deformation after work completion. The processing of historical satellite data archives acquired over the last two decades provides a ground deformation baseline (e.g. identification of pre-existing ground movement) and contributes to estimating the impact of tunneling activities. Applications of InSAR in tunneling projects will be presented, illustrating the advantages of integrating InSAR monitoring into all phases of the construction.