A roof-rib pillar support system is often formed in the metal mines that applied to the backfill mining method. In order to ensure the safe mining

it is of great significance to explore the failure mechanism of the roof-rib pillar support system under backfill mining. On the basis of considering the side pressure effect of the backfill on the rib pillar

a mechanical model of the roof-rib pillar support system under backfill mining was established. Furthermore

the catastrophe theory was used to explore the failure mechanism of the supporting system under the action of the filling body

and the influence of the structural parameters of the support system before and after filling on the stability of the stope was analyzed. The research results show that under the condition of certain mechanical properties of the rock mass

the stability of the roof-rib pillar support system under backfill mining is controlled by the stope structure parameters (roof thickness

stope span

rib pillar width

rib pillar height)

the overburden load and the side pressure of the backfill. The addition of the filling body will reduce the stiffness ratio of the support system

thereby improving the stability of the stope. When the stope is at an unfilled state

the optimization sequence of the structural parameters of the support system should be roof thickness

stope span

rib pillar width and rib pillar height. When the stope is at the state of filling

the optimization sequence should be roof thickness

rib pillar width

stope span

and rib pillar height. The combination of theoretical derivation and numerical simulation is applied in the supporting project to verify the correctness of theoretical derivation.