Study on surface subsidence characteristics and overburden development process of pillarless caving mining method based on time-series InSAR technology

In the West No.2 Mining Area of Longshou Mine, mastering the trends of surface subsidence and the development process of underground overburden is crucial for analyzing mining progress and assessing mining safety. This study proposes the use of SBAS-InSAR technology combined with bicubic interpolation to achieve continuous monitoring of surface subsidence trends. Based on the monitoring data, we analyze the rock stress changes induced by mining operations and further infer the formation and evolution of the underground overburden. The results of the study show that: (1)A typical subsidence funnel formed above the mining area, with significant uplift in the northeast direction of the mining area; (2)Different regions exhibited varying trend changes during the study period; (3)Through time-series analysis of characteristic points, key nodes of rock stress changes were identified, and the overburden formation process was divided into three stages: ①Early mining stage, where mining operations had a small impact and the overburden had not yet started to form; ②Formation stage, where the roof strata gradually collapsed and thickened to form the overburden, and surface subsidence accelerated significantly; ③Stable subsidence stage, when the overburden had been mostly formed, and the subsidence rate stabilized.The study concludes that SBAS-InSAR technology combined with bicubic interpolation can not only dynamically monitor surface subsidence trends but also indirectly reveal the evolution of the overburden. The results are highly consistent with those observed in GNSS and microseismic monitoring. This technology demonstrates unique advantages in mining safety analysis, providing a reliable and continuous time-series perspective for mining progress analysis and safety assessment.