Numerical study of pressure on dams in a backfilled mining shaft based on PFC3D code

In all EU countries, the number of actively operational coal mines continues to decrease. This decrease requires the closure of unnecessary shafts, which is a very complicated task. Currently, the most commonly used method of shaft closure involves building dams and locking plugs in the area of insets and subsequently backfilling with a granular material. The design of the dams and locking plug should take into account the horizontal and vertical pressure in the backfilled shaft. This paper presents a comparison of the results obtained from the analytical (Janssen’s theory) and numerical calculations, as well as an analysis of the changes in the load of the dams, depending on their location relative to the shaft. The numerical approach was developed using the method of discrete elements implemented in the commercial software PFC3D (Particle Flow Code in 3D). The analysis was performed in the framework of the “MISSTER” project (RFCR-CT-2010-00014: Mine Shafts: Improving Security and New Tools for the Evaluation of Risks).