Failure mode and damage assessment of underground reinforced concrete arched structure under side top explosion

Reinforced concrete arch constructions offer practical building methods and favourable mechanical properties. The utilization of this technology is prevalent in the field of underground engineering. The present study investigates the failure mode and damage assessment of an underground, reinforced concrete-arched structure subjected to a lateral-top explosion. A series of four tests were formulated and executed to examine the dynamic response characteristics of the construction. These tests involved manipulating both the explosion distance and charge mass variables. The LS/DYNA software created an extensive three-dimensional model, including the rock, concrete, and steel bars. A numerical simulation was conducted to analyze the dynamic response process of a reinforced concrete arched structure. The simulated failure characteristics of the arched structure exhibit a high level of concordance with the experimental findings. In light of this, simulations were conducted to analyze the failure mechanisms of the arched structure when subjected to varying blasting distances and charges. The study's findings indicate that the primary mechanisms of failure observed in underground arching structures subjected to side-top blasting include spalling, shear, bending, and mixed bending-shear failure of concrete. A comparative analysis examined the impact of charge mass and blasting distance on the arch waist's radial displacement and the side wall's rotation angle. The level of damage was partitioned, and a criterion for assessing the damage to the structure was put out. The establishment of the omega-R (TNT equivalent blasting distance) curve for measuring the damage levels of an arch under a side-top blast was based on the damage grades and damage criteria.