Performance analysis of base-isolated structures in mitigating underground blast-induced ground motion effects: A parametric study

This study delves into mitigating ground motion induced by underground blasts on superstructures. A parametric analysis is conducted to assess the performance of base isolated structures under different blast scenarios. The analysis is conducted using Newmark's time step integration method, and the absolute acceleration of the structure and displacement of the isolator bearing are calculated to evaluate the response. Results demonstrate the significant effectiveness of base isolation in reducing blast-induced vibrations. The parameters of the base isolator, including damping ratio and time period, are systematically varied to understand their impact on the response. Key findings include the significant influence of the ground medium on both fixed base and base isolated superstructures, with soil-rock interface locations reducing floor acceleration under various blast load intensities. The N-Z bearing system is shown to effectively reduce the dynamic response in both rock and soil media. This study recommends specific combinations of ground medium and site location for optimal protection against blast threats. Ultimately, this study facilitates a better understanding of the dynamic interaction between underground blasts and superstructures, paving the way for more effective blast-resistant structural designs.