Application of SBAS-InSAR and PS-InSAR technologies in analysis of landslide subsidence along a linear infrastructure in Southwestern Shandong

Land subsidence is a serious problem that affects the construction of traffic engineering in the economic development zone in southwestern Shandong Province. This paper selects the range of 5 km on both sides of a linear project as the research area. The article collects RadarSAT-2(2017-2020), Sentinel-1A(2019-2020) archived data , geological data, hydrogeological data, and mineral development data, and uses time-series InSAR measurement to analyze the distribution characteristics and laws of land subsidence in the study area. The research indicates: the main causes of ground subsidence in the study area are coal mine goaf collapse and excessive groundwater mining; the former forms a settlement funnel with the mining area as the center, the change of settlement rate and the movement of the settlement center are closely related to the mining progress and transfer of the coal mining area; The latter’s settlement distribution law is related to the distribution of groundwater use areas, forming a subsidence zone that similar to the range of groundwater mining. The study area continued to experience subsidence during 2017 to 2020, with the maximum annual subsidence rate at 136.5 mm/a, and the cumulative maximum subsidence in a single year at 220 mm. After checking the observation results of CPI benchmarking points during the same period, the average error of InSAR data processing results is less than 1cm/a, and the correlation coefficient is more than 70%. The analysis method adopted in this paper can timely and accurately reflect the changes in land subsidence throughout the study area, provide effective and reasonable reference for route planning and geological disaster remediation.