Study on damage characteristics and mechanisms of arch concrete slabs with outer arch side facing water under inner-arch contact explosion

Abstract

The anti-explosion performance of the arch concrete slabs under different working conditions is an important subject that has been widely studied in recent years. In this study, five arch concrete slabs with 60 mm thickness and different spans (500, 550, and 600 mm) with the outer arch side facing water were tested under inner-arch contact explosion. At the same time, the controlled explosion test of the arch slab with the outer arch side facing air was also carried out. The experimental results showed that the damage mode of the arch slabs with the outer arch side facing water was mainly long axial cracks on the mid-span, blasting pit on the inner arch side and radial cracks on the outer arch side. The crack development of the control group specimen was more complete, and there was greater and deeper spalling damage on the outer arch side. Moreover, a fully coupled model of contact explosion was established based on the Lagrange–Euler coupling algorithm, and the reliability and accuracy of the model were verified by comparing with the experimental results. The propagation laws of stress waves in arch slab was then studied. The dynamic responses of arch slabs with different working conditions and spans were studied, and the damage mechanisms of arch slabs were also analyzed. The results showed that, under the same explosion load, the arch slab with the outer arch side facing water exhibited more uniform stress than the arch slab with the outer arch side facing air. And the acceleration response showed that, the arch slab with the outer arch side facing air mainly deformed along the explosion direction, but the arch slab with the outer arch side facing water not only deformed along the explosion direction but also had a rebound trend. Moreover, because of the existence of the water interface, the transmission of compression stress wave in the arch slab increased and the reflection decreased when it reached the outer arch surface.