Abstract
The protection of underground infrastructure from modern missiles has become a critical engineering challenge for countries involved in military conflicts. This study presents a numerical investigation of the stress–strain response and blast resistance of underground tunnel structures subjected to a ballistic missile impact. The analysis was conducted for typical soil conditions of the Kyiv region (Ukraine), where sandy soils prevail at shallow depths. ANSYS Explicit Dynamics, combining Eulerian and Lagrangian solvers, was used. The propagation of blast waves in the soil mass, the formation of a blast crater, and the resulting stress distribution were analyzed for cases without protection and with reinforced concrete protective slabs of varying thicknesses. The results demonstrate that surface protection significantly alters blast wave characteristics and reduces peak stress in the near‐surface zone, although excessive slab thickness may shift stress concentrations to a deeper zone. An express assessment method was proposed, based on the ratio between peak stresses in the soil and tensile stresses in the tunnel’s support, enabling rapid estimation of safe depth and required protective slab thicknesses. The proposed approach can contribute to rapid decision‐making for the protection and design of underground infrastructure.