ABSTRACT
As a rule, saliferous rock and potash deposits are developed using the room-and-pillar method. Field studies demonstrate that the thin-layered structure of a saliferous rock deposit and presence of clay bands reduce the durability of stope roofs. Therefore, it increases the deformation rate of rib pillars and leads to a gradual loss of bearing capacity.
This work presents the results of experimental and numerical studies of the stress-strain behavior of the bearing elements of the room-and-pillar method. The theoretical description of deformation and fracture of saliferous rocks was based on the elastoplastic models of the medium. The deformation of contacts was determined using their full failure diagram. Instrumental monitoring results were used for the mathematical model calibration. The paper formulates the criterion of the chamber roof collapse based on the field observations and numerical study results. The critical rates of the transverse deformation of pillars were estimated. The verification of the modelling results for the deformation and fracture processes of bearing elements of the room-and-pillar method proved an appropriate conformity to the field data.
