Research on Impact Compression Strength and Explosion Resistance of Layered Gradient Rubber Concrete in Underground Engineering

In today’s world, terrorist bomb attacks and sudden explosion accidents bring serious challenges to underground engineering. Improving the dynamic protection capability of underground engineering is an important social and scientific problem that remains to be solved. Rubber concrete (RC) has an outstanding application prospect in the field of dynamic protection in underground engineering due to its excellent buffering and energy absorption characteristics. Functionally gradient material is a kind of material that can be designed according to the actual situation. This paper combines the concept of functionally gradient material (FGM) with traditional rubber concrete, proposing a new material: layered gradient rubber concrete, and explores the impact compression resistance and anti-explosion performance of specimens with different gradient modes based on Hopkinson pressure bar testing and LS-DYNA (a finite element software). The results show that there is a strain rate effect in layered gradient rubber concrete, and its failure starts at the weakest strength layer. Considering the stress–strain curve, DIF value and toughness index of the specimens, the concave gradient mode can effectively improve the impact compression performance of traditional rubber concrete. Through numerical simulation, the anti-explosion ability of layered gradient rubber concrete was tested. The concave gradient rubber concrete has the best attenuation effect in the face of explosion stress waves. Compared with the homogeneous rubber concrete, the stress attenuation effects on the structure surface X0, X1.5 and X3 of the concave gradient mode were improved by about 15, 25 and 43%, respectively.