The Stability Analysis Method of Leveling Datum Points in Mining Areas of Western China Based on SBAS-InSAR Technology

The Stability analysis of datum points is a fundamental procedure to verify the monitoring results of leveling settlement. Traditional methods tend to be the employment of repeated monitoring or the increase in measurement points under the same monitoring technique, which are costly and complicated in data processing, making them difficult to be applied in common ground subsidence monitoring scenarios. In view of this, inspired by the idea of external validation, this paper proposes an evaluation method of the stability of datum points in leveling Observation based on Small Baseline Subset InSAR (SBAS-InSAR) technology. Firstly, the paper indicates that differences of subsidence measured by SBAS-InSAR and ground leveling of the same location respectively within close proximity are primarily composed of error caused by unconformity of the position, observation time and measurement method error as well as the displacement of datum points. Based on that, the formulas of calculating errors of unconformity of observation time and the displacement of datum points are derived separately. Afterwards, taking the monitoring of surface subsidence caused by the mining of two working faces in Yingpanhao Coal Mine located in northern Ordos Basin, as practical applications, the feasibility of the method proposed in the paper is verified. And the scope of application of the proposed method is also suggested. This study provides an efficient and economical solution for evaluating the stability of datum points in leveling settlement monitoring, promoting the joint combination of SBAS-InSAR technology and traditional leveling when applied to surface subsidence monitoring.