Dynamic Responses and Design Suggestions of Anti-Explosion Chambers Under Large Equivalent Explosion Loads

In response to the lack of design data for explosive charges greater than 100 kg trinitrotoluene (TNT) in the current Design Code for Blast-Resistant Structures (GB 50907—2013), the study utilized the explicit finite element software LS-DYNA to simulate the dynamic responses of blast-resistant chambers under large-equivalent explosion scenarios. A parametric analysis was conducted on various design parameters to investigate their impacts on the structural performance of the blast-resistant chamber, and design recommendations were proposed.Firstly, the accuracy of the simulation model was verified by comparing the finite element results with existing blast test data, showing errors of 4.7%, 12.9%, and 2.3% for panels P2-1, P2-2, and P2-3, respectively. Secondly, the study analyzed the stress variations in the blast-resistant chamber under the equivalent of 100-200 kg TNT, revealing that when the TNT equivalent reached 160 kg, the wall reinforcement entered the plastic deformation stage. Based on this, further analysis was carried out to assess the effects of different design parameters on the load-bearing capacity of the blast-resistant chamber at the 160 kg TNT equivalent. The results indicated that within the range of 100 kg to 200 kg TNT, plastic zones initially formed in the tensile region at the base of the sidewalls and gradually expanded outward. The wall panel connections emerged as the primary areas of stress concentration.Based on the analysis, it was recommended that the wall thickness of the blast-resistant chamber should be between 600 mm and 900 mm, with the concrete strength not lower than C50, the rebar yield strength not less than 300 MPa, and the rebar diameter not smaller than 22 mm. The reinforcement ratio for the walls should exceed 0.3%, and haunched diagonal rebars at the wall panel connections should be chosen at 4/5 of the main rebar diameter.