The effect of material properties on growth rates of folding and boudinage: Experiments with wax models

摘要: Abstract The growth of unstable structures was studied experimentally in layered wax models. rheological properties the two types were determined independently by a series cylinder compression tests. Both waxes enhibited (1) non-Newtonian stress vs strain-rate relationship (2) strain softening and (3) temperature-dependent viscosity. stress-strain-rate relationships approximated power-law, with exponents 5 for microcrystalline 1.8 paraffin wax. Blocks single embedded layer deformed two-dimensional pure shear oriented either parallel to compressive axis so that it shortened folded, or perpendicular would stretch boundinage form. rates tiny initial disturbances measured. folding boudinage much higher than could be accounted theories assuming Newtonian material properties. Theories taking behaviour into account (Smith, R. B. 1975. Bull. geol. Soc. Am. 86, 1601–1609; Fletcher, C. 1974. J. Sci. 274, 1029–1043) better describe rates. Boudinage, however, grew almost three times faster predicted even existing theory. A possible reason this discrepancy is do not exhibit steady-state creep as assumed We, therefore, extend theory include strain-softening. crucial step use scalar measure deformation state variable constitutive law. In way isotropic manifestation strain-softening can taken account. analysis shows lead greatly increased while having little influence on folds, which agreement experiments.