Experimental study on the dynamic mechanical properties of high-performance hybrid fiber-reinforced concrete of mine shaft lining

Deep mine shafts are susceptible to rupture under dynamic loading. To solve this problem, hybrid fiber-reinforced concrete (HFRC) is proposed as a construction material for mine shaft lining. Herein, its dynamic mechanical properties are experimentally studied. With high-strength shaft lining concrete as the reference, HFRC specimens are prepared by mixing polyvinyl alcohol fibers and imitation steel fibers at different volumetric ratios. Falling-weight impact tests demonstrate that the first-crack and failure impact energies of the HFRC are 2.4 and 20.0 times to the reference concrete, respectively. In addition, the HFRC provided better cracking resistance and higher toughness. Split Hopkinson pressure bar tests demonstrate that compared with the reference concrete, the peak stress and peak strain of the HFRC under a 0.7 MPa impact air pressure are increased by 46.19% and 34.11%, respectively. The toughness index is increased by 50.51% within the strain range from 0 to 0.008. These results indicate that compared with the reference concrete, the HFRC has significantly higher dynamic strength and compressive deformation capacity with well-improved brittleness; further, it can effectively resist impact loading under variable strain rates, thereby making it an ideal supporting material for mine shaft lining under dynamic loading