Explosion-induced free-field ground motion measurements in sodium chloride closely follow simple cube root scaling laws over 10 orders of magnitude of explosion energy (from 0.6 to 2.2 × 1010 kJ). This observation has important implications for the use of scale model experiments in simulating many of the effects associated with large chemical and nuclear explosions. Small-scale experiments in polycrystalline sodium chloride have been conducted using chemical explosives with energies between 0.6 and 300 kJ. Measurements at various confining pressures up to 32.2 MPa show that both cavity volume and free-field motion produced by explosions in pressed salt are independent of confining pressure. Within a scaled slant range (the radial distance to the center of the energy source) of about 80 m/kt1/3, the salt undergoes shear failure of the matrix (deformation which is both inelastic and nonlinear). Beyond 80 m/kt1/3 and to 250 m/kt1/3 (where these data end), the deformation continues to be strongly inelastic, but the magnitude of this inelasticity appears to decrease with range. Furthermore, measurement at a slant range of 168 m/kt1/3 of the combined signals produced by two simultaneous charges (separated by 191 m/kt1/3) shows little, if any, deviation from linearity.

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