3D modelling of the strength effect of backfill-rocks on controlling rockburst risk: a case study

Rockburst is a typical form of dynamic disasters in coal mines. Reducing the risk of rockburst is an important measure to ensure safety and safe production from coal mines. According to the geological conditions of Hengda coal mine, the deformation deflection equation of the roof and the deformation energy equation of the surrounding rocks are derived from the elastic thin plate theory model. Based on these equations, the criterion of the elastic energy density was updated. Then, the roof movement, stress distribution, and elastic strain energy evolution law of the working face when employing different strengths for the backfill-rocks were analyzed using FLAC-3D. A method aiming to reduce the risk of rockburst by quantitatively adjusting the strength of refilled rocks was proposed. The results show that increasing the strength of refilled rock can effectively control the roof subsidence of the working face and improve the concentrated distribution of stress around the goaf during backfill mining. At the same time, it can effectively reduce the degree of the influenced area and the stress concentration in front of the working face and the elastic strain energy of the roof to minimize the risk of rockburst.