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    Cavities Produced by Underground Nuclear Explosions
    (Lawrence Lovermore Laboratory, 1976-07-08) Butkovich, T.R.
    This investigation studied the displacement of rock that formerly occupied cavities produced by underground nuclear explosions. There are three possible explanations for this displacement: the volume could be displaced to the free surface; it could be occupy previously air-filled pores removed from the surrounding rock through compaction; or it could be accounted for by persisting compressive stresses induced by the outgoing shock wave. The analysis shows it unlikely that stored residual elastic stresses account for large fractions of cavity volumes. There is limited experimental evidence that free surface displacement account for a significant portion of this volume. Whenever the explosion mediums contain air-filled pores, the compaction of these pores most likely accounts for all the volume. Calculations show that 4% air-filled porosity can account for all the cavity radii and that even 1% can account for a significant fraction of the volume.
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    Rock Modeling in TENSOR74, a Two-dimensional Lagrangian Shock Propagation Code
    (Lawrence Livermore Laboratory, 1975-03-19) Burton, Donald E.; Schatz, John F.
    TENSOR74 is a major revision of TENSOR, a computer code designed to solve stress wave propagation problems in two dimensions. The major physics modificatims in TENSOR74 are in the area of constitutive modeling of solid materials. The new models, which are described in detail, take into account pore collapse, ductile and strain softening brittle failure, as well as tensile failure with void opening and closure. In addition, a modified form of linear artificial viscosity is described.
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    SOC73, A One-dimensional Wave Propagation Code for Rock Media
    (Lawrence Livermore Laboratory, 1974-11-05) Schatz, John
    SOC73 is a highly modified version of SOC, a computer code that numerically stimulated mechanical wave propagation in geologic media. Innovation in SOC73 lies mainly in the constitutive modeling of solid media. New models have been introduced in which the pressure-volume behavior and the behavior of brittle, ductile, and tensile failure are more continuous and representative of laboratory and field observations than before. There are also new methods of low-pass compressional filtering and high-pass distorsional filtering that are more physically and numerically satisfying. Finally, the concept of failure-associated strain has been introduced. It allows an estimate of the damage caused to the medium by an inelastic stress wave.