Evaluating Potential Ground Subsidence Geo-Hazard of Xiamen Xiang’an New Airport on Reclaimed Land by SAR Interferometry

Guanchen Zhuo,Ye Feng,Keren Dai,Jin Deng,Shengpeng Li,Xianlin Shi,Xiujun Dong,Huina Huang,Tao Li

doi:10.3390/su12176991

Abstract

The land reclaimed from the seaside may have a long-term subsidence trend, which poses a potential geohazard in the future land use. Xiamen Xiang’an New Airport (XXNA) is built on reclaimed land since 2016. Based on the spaceborne Sentinel-1 data between January 2018 to April 2019 and the time series interferometric synthetic aperture radar (InSAR) technique, this paper analyzed the reclaimed land subsidence evolution at XXNA in this period. InSAR measurements show that XXNA is suffering from severe subsidence, mainly in three regions because of the earth and sand compacting. By analyzing the spatial subsidence characterizations of the main subsiding areas combined with historical land reclamation and future land use planning, we find the potential threat of subsidence to future land use. Correlation between subsidence and the period of reclamation was found, indicating that the consolidation and compression in dredger fill is the main cause of subsidence. By combining subsidence monitoring results with different land use types and adopting the Expectation (Ex) and Entropy (En) methods, we analyzed the key area with potential subsidence geo-hazard. This work shows that with SAR interferometry, it is possible to find the large area ground subsidence in the airport reclaimed area. The areas with potential subsidence geo-hazards are consistent with the deep reclaimed earth, which means high subsidence risk in the future.

Highlights

With the urbanization and economic development in coastal areas, land resources are becoming increasingly scarce
Liu et al [8] employed SBAS-interferometric synthetic aperture radar (InSAR) technique to determine the temporal and spatial evolution of ground settlement at Xiamen Xiang’an New Airport (XXNA) combined with land reclamation
In the SBAS method, it is assumed that the surface subsidence in the interval between the acquisition of two adjacent SAR images conforms to the linear cumulative trend [39], and the solution of the phase time series is converted into the solution of the phase change rate

Summary

Introduction

With the urbanization and economic development in coastal areas, land resources are becoming increasingly scarce. To meet the development needs of coastal cities, humans have to reclaim land from the seaside all over the world, such as Shenzhen (China), Shanghai (China), Urayasu (Japan), New Orleans (USA), and Venice (Italy). All of those cities [1,2,3,4,5] have suffered from the land subsidence hazards due to long-time and gradual soil compaction on reclaimed land, which would cause damage to important infrastructures (e.g., airports, roads, buildings, and metros) and pose a great threat to the environment and public safety [6]. Liu et al [8] employed SBAS-InSAR technique to determine the temporal and spatial evolution of ground settlement at XXNA combined with land reclamation (with Sentinel-1 images from 2015 to 2018). We discussed potential risks of subsidence at XXNA by different quantitative statistical indicators

Location of XXNA and Land Use Planning

Discussion

Findings

Conclusions