Physical foundations for approximately modeling explosions with ejecta

Various cases of exact and approximate similarity are examined for underground explosions with the ejection of earth material. Attention is given to a contradiction between current representations of the similarity law and the reduced data of large-scale experiments. A refined phenomenological theory is presented. A possible similarity of the ejecta is shown for identical materials. These representations are in agreement with more precise reductions of experimental data. Convenient dimensionless parameters are presented which are the basis for an approximate method for modeling large-scale explosions under laboratory conditions.