Beijing subway tunnelings and high-speed railway subsidence monitoring with PSInSAR and TerraSAR-X data

Tremendous underground exploitation as subway tunneling, functional facilities excavation in inner-city environments caused potential damages to buildings and bridges over the construction zone. PSInSAR technique and high resolution SAR data provides a powerful tool for slightly surface deformation in recent years. Till now, it is time to use PSInSAR as an operational and mature technique for geodesy and geodetic purposes. In this work we presented the monitoring of subsidence over subway tunnels and along high speed railway in Beijing city by interferometric time series analysis based on nearly 46 scenes of TerraSAR-X data over the past 4 years. The resulted velocity map described the extent and magnitude of subsidence along the subway lines due to the different ground excavation method. It demonstrated that the total subsidence of PSs over the tunnels caused by open-cutting method is up to 70-80 mm and that caused by tunneling method is only 15-25mm in the full construction cycle of subway tunnels. The subsidence extent is distinguished different relying on the excavation method as well as the load of ground buildings. Under the same condition the subsidence over the built up area is more significant than that over the general area.