Experimental and numerical investigation of arch concrete slabs subjected to underwater contact explosions with the inner arch side facing air

Arch structures with their inner arch side exposed to air and outer arch side exposed to water are often encountered in practical projects, and these engineering structures may be subjected to various explosive attacks during operation. This paper investigates the damage mechanism and dynamic response of arch concrete slabs with the inner arch side facing air against underwater contact explosions (UWCEs). The explosion tests of the arch concrete slab with the inner arch side facing air were carried out. The accuracy and applicability of the numerical model were verified by comparing with the explosion results. After that, the failure evolution and energy transition of the arch concrete slab with the inner arch side facing air were studied. The effects of different explosion masses, explosion distances, and reinforcement schemes on the antiknock performance of arch concrete slabs are further explored. The results show that as the explosive mass of UWCEs increases, the damage mode of the arch concrete slab with the inner arch side facing air changes from cracking along the longitudinal direction and local failure to spalling on the inner arch side and fragmentation of the contact specimens. The existence of curvature of the arch slab will cause the damage of the arch slab to intensify. The failure mode of the arch concrete slab changes from local failure to slight failure with cracks as the explosion distance increases. Increasing the longitudinal steel bars on the outer arch side can effectively inhibit the generation and development of cracks.