Abstract: To study the uniaxial compressive strength calculation method of rock-steel fiber reinforced concrete (R-SFRC) composite layer, uniaxial compression test was carried out on rock, steel fiber reinforced concrete and R-SFRC composite layer specimens. The influence of concrete strength grades (C30, C40 and C50) and fiber contents (0, 40, 60 and 80 kg/m3) on the uniaxial compressive strength of steel fiber reinforced concrete and composite layers was analyzed. RFPA2D was utilized to simulate the damage process and stress-strain curve of the composite layer under uniaxial compression. The compressive strength prediction model of R-SFRC composite layer was established based on Mohr-Coulomb yield criterion. The results showed that the uniaxial compressive strength for composite layer specimens was between the compressive strength of rock and concrete. The mutual restriction of rock and concrete interface in the composite layer changes the stress state of each layer. The strength of rock in the composite layer decreases while the strength of concrete increases. The ultimate compressive strength of composite layer is the strength of concrete in the composite layer. The compressive strength of composite layer specimen increases with increasing concrete matrix strength and steel fiber content, and effect of concrete matrix strength was more significant. For the uniaxial compressive strength of composite layers of different materials, the error ranges of the numerical simulation value and theoretical calculation value relative to the experimental value are -5.41%～-0.69% and -8.67%～-1.21% respectively. Numerical simulation and theoretical calculation models can be used for uniaxial compressive strength prediction of composite layers.

Key words: rock, steel fiber reinforced concrete, composite layer, compressive strength, numerical simulation, Mohr-Coulomb yield criterion