Mathematical model of a blocky medium with elastic-plastic clusters-blocks and thin compliant, rheologically complex interlayers is applied at the mesoscale level to the analysis of plastic deformation and fracture of structurally inhomogeneous materials under the action of dynamic disturbances. The model takes into account the contact interaction of blocks in the presence of an initial system of cracks in the interlayers and cracks formed during the process of deformation of the material. Preliminary stresses that are formed in blocks during production are modeled using the example of cooling of glass melt based on the consideration of the influence function characterizing the mutual influence of the structural elements of a medium onto their volumetric strain. A heuristic principle of maximum entropy is formulated, which allows constructing and analyzing fields of preliminary strain in samples. Within the framework of the model of a pre-stressed blocky medium, we study the mechanism of appearance of self-sustaining fracture waves in tempered glass, caused by the release of a stored energy of initial stresses as plastic waves pass through the blocks.