The aim of this paper is to describe a new discrete method for the evaluation of local damage to the bearing system of underground structures. The discrete boundary element method, which serves as a numerical means for detecting local cracks, has been used in the past either as a general means for identifying sites with cracks or for assessing the possibility of bumps occurring in underground mines. Newly, this method is non-trivially extended to the combination with non-linear Navier-Stokes equations, which are solved by finite volumes used to describe the propagation of air movement that creates a subsonic pressure wave in the free space within the structure. Interaction of waves along the boundary of both phases is ensured by interfacial conditions, which correspond to the combination of both numerical means - discontinuous boundary elements and finite volumes. To maintain compatibility of both environments, discretization of both air and solid is based on hexagonal meshes. Two typical examples demonstrate the suitability of the method showing an initial (critical) state of the development of pressure waves and the condition of damage to the structures of underground parking.