Dynamic responses of underground arch structures subjected to conventional blast loads: Curvature effects

The present study explored dynamic responses of underground circular arch structures subjected to subsurface conventional denotation. Analytical solutions were obtained through the modal superposition method. The soil–structure interaction, behaving as an interfacial damping, was included and the effect of different soils was investigated. Two soil–structure interaction models were discussed and compared. In Model I, the curvature of the structure surface and the arrival time difference were considered, while in Model II, the curvature of the structure surface was ignored but the arrival time difference to the structure was considered. Due to the complexity of the arch structure, a simplified structure model, neglecting the effect of shear and rotary inertia, was employed. The time histories of displacement, velocity and acceleration were predicted. Distributions of maximum moment and displacement were plotted using the result of responses. Blast loads in elastic designs were suggested and potential failure modes were predicted. Considering the curvature effect, Model I suggested greater reflection factors and dynamic loads subjected to the arch. Safety of structure could be evaluated by the results of responses. For safety purpose, the protective structures are better to be constructed in a site with small acoustic impedance and a large attenuation factor.