Numerical modelling and empirical tool for subsidence prediction by the use of backfill

International audienceGeomechanical-numerical methods are an established tool for planning of underground excavations worldwide. By describing the interaction between rock mass and backfill it is possible to determine the suitability of backfill methods regarding subsidence and a potential increase of the extraction ratio. DMT and INERIS, both have longterm experience in investigating and applying geotechnical parameters for designing and refining numerical models for planning and evaluating almost any underground excavation-project by geomechanical-numerical tools combined with empirical planning methods. The presentation describes the planning approach for numerical models in mining and illustrates the advantages of this planning tool by means of several planning cases from the mining industry worldwide. The paper also describes the development of an empirical approach visualizing the backfilling effect on the prediction of subsidence of deep mines. The estimation of the effect of backfilling may be obtained by in-situ measurements and by the numerical modeling. A basic 2D numerical model was used to estimate the factor of subsidence reduction due to the backfilling exemplary for a room and pillar mine