Explosion of a charge in a ground (1988). The charge is modelled as a high temperature and pressure gasous media, which occupies small hole near day surface at initial time instant. The groud has properties of typical geomaterial (porous plastically compressible elastic plastic media). The gas and the ground are considered as two separated "bodies" represented by two separated Lagrangian moving grids, interacting in accordance with contact conditions. Code ASTRA.