Study on dynamic compressive strength model of rock-steel fiber reinforced concrete composite layer

In order to study the compressive strength model of rock-steel fiber reinforced concrete (R-SFRC) composite layer under impact loading, the dynamic impact compression tests of granite, concrete and R-SFRC composite layer were carried out by using the separated Hopkinson pressure bar to obtain the dynamic compressive strength of different materials. With the regression fitting of the experimental results, three types of R-SFRC composite layer strength models called logarithmic, power function and strength-strain rate dependent mechanism were obtained, and dynamic compressive strength models of the R-SFRC composite layer were established based on the Mohr-Coulomb strength criterion considering the interface interaction of the R-SFRC composite layer. The results show that the dynamic compressive strength of the R-SFRC composite layer N2301023models is 0.918-0.999, and the R2 of the dependent mechanism model is the largest. The error range of the theoretical value of dynamic compressive strength calculated based on the Mohr-Coulomb strength criterion relative to the experimental value is -9.67%-3.16%, and the maximum error value of the logarithmic model is smallest. The calculation model of dynamic compressive strength of R-SFRC composite layer can provide a theoretical basis for the concrete supporting tunnel surrounding rock design.