Asymmetric Deformation Induced by Underground Mining: A Case Study of a Mine in Shaanxi, China

Geohazards resulting from mining activities must be effectively monitored to mitigate their impact on the environment and human activities. Geohazards such as landslides and collapses caused by open-pit mining are relatively easier to monitor because they are primarily surface-based. In contrast, underground mining disrupts the stress balance in the overlying rock layers, leading to complex settlement patterns, including subsidence basins, cracks, and groundwater depletion. This complexity makes monitoring geohazards caused by underground mining particularly challenging, as it depends on subsurface stress conditions and structural complexity. Previous studies have shown that land subsidence caused by horizontal/near-horizontal longwall mining methods is typically symmetrical. However, asymmetry can occur under complex conditions. In this paper, asymmetric land subsidence caused by coal mining activities in Shaanxi, China, over the past decade is investigated using Interferometric Synthetic Aperture Radar (InSAR) supplemented by field investigations and geophysical experiments. The results indicate that the mining across multiple working faces over the years has led to the formation of a large subsidence funnel above the working faces with a cumulative subsidence of more than 900 mm in the centre area, in addition to the formation of a new subsidence centre. Moreover, asymmetric surface deformation has also occurred, with both the extent and magnitude of deformation being greater on the southwest side of the working faces than on the northeast side. Through further analysis, we proposed potential driving mechanisms of asymmetric subsidence, providing valuable insights into the prediction and monitoring of land subsidence due to underground mining.