Experimental Study on the Interaction between Backfill and Surrounding Rock in the Overhand Cut-and-Fill Method

Backfilling is commonly used in underground mines to improve the stability of overlying strata. The performance of the backfill and its interaction with surrounding rock are the key issues in backfill mining research. In this paper, the displacement and stress field evolution characteristics of the overlying strata in backfill mining were analyzed by a physical model, as well as the interaction between the backfill and surrounding rock. The research results show that when backfill mining is employed, the backfill mass and the unexcavated rock mass jointly bear the loads of the overlying strata. The loads of the overlying strata are transferred to the dense backfill mass and the surrounding rock. The stress in the near-field area of the surrounding rock increases and stabilizes gradually. The backfill mass improves the stress distribution state and reduces the stress concentration of the surrounding rock, which is conducive to preventing the progressive damage of the overlying strata. In addition, the backfill mass excavation has a significant influence on the stability of the overlying strata and the surrounding rock stress field. The backfill mass is a passive force-bearing structure that can effectively manage the deformation of the overlying strata and the phenomenon of underground pressure.