Reducing surface subsidence risk using solid waste backfill technique: A case study under buildings

Abstract

Coal mining-induced surface subsidence causes many environmental problems and geological hazards, including damage to buildings, depletion of water resources, and land desertification. However, numerous coal resources in China are buried under buildings. To solve these problems, a solid waste backfill mining (SWBM) technique has been proposed to control the surface subsidence under buildings. This paper introduced the fundamental principle of the SWBM technique and then presented a model based on the theory of equivalent mining height (EMH) to predict surface subsidence. In addition, the compaction effects of backfill materials were obtained through an experiment on the compaction properties thereof. Afterward, measuring transects were arranged to conduct field observation of surface subsidence: when the backfill materials are sufficiently compacted, the compression degree is 0.13 with 13% deformation. Moreover, the measured maximum subsidence was 18 mm, which is lower than that predicted for the maximum deformation of a nearby building. In addition, surface buildings were slightly influenced by coal mining and no obvious cracks were found. Therefore, this technique provides a new approach for controlling the surface subsidence induced by coal mining.