Abstract: Rock mass,rock bolts and cement mortar are regarded as the composite reinforced material of anchored rock mass.A layered model of anchoring composite material is established according to the principle of strain energy equivalent and mechanical properties of anchoring rock mass are studied quantitatively.Based on above analysis,the space between rock bolts arranged in sector will increase with the anchoring depth growing,and the equivalent mechanical properties of the reinforced rock mass will vary when the space between rock bolts changes.Functions of equivalent mechanical parameters related to the rock bolts anchoring depth of the underground cavity anchoring composite material are deduced and deformation stability is analyzed with the finite element methods to verify the theoretical analysis.So the anchoring mechanism of the rock bolts arranged in sector in the underground cavity will be realized more clearly.

Key words: Underground cavity, Anchoring rock mass, Composite reinforced material, Equivalent mechanical property, Anchoring mechanism