Plastic Damage of Mylonite Parent Rock and the Numerical Simulation of Porous Media Brittle Crush

Abstract: Mylonite is a kind of dynamometamorphic rock. Its' particular formation mechanism makes itself a carrier of rich geology information. The study and research of mylonite is significant not only in theory but also in practice. Many geology scholars are being absorbed in observing and investigating it.Aimed at some bewildering phenomena of mylonite formation study, this thesis theorizes the meso-damage mechanical RVE (representative volume element). of mylonite parent rock according to the porous media which are put forward in literature [40]. Mylonite is thought as the result of mylonite parent rock's brittle crush after it is porosity damaged plastically. RVE is calculated with the finite element method and the Mohr-Coulomb damage rules are employed to analyse the calculation result. It is fined that the porous media's crush is completely possible on the condition that mylonite is formed and that the tectonic stress is the major factor but the confining is the minor factor on porous media's crush.Based on the result, a series geology phenomena are explained such as plastic and brittle distortion, plastic flow structure, strip-shaped output and so on. The great difference of micro-texture among ultramylonite, mylonite and early mylonite can be well explained in this thesis.Crystal diminish phenomenon is given a half quantitative analysis at the end of the thesis. The proportion of porphyroclast in mylonite micro-texture is also calculated and the explanation of the difference between the final result and the micro-observation is presented…
Key words: mylonite; meso-damage mechanics; effect of confining; hydrolytic attenuation; degree of stress triaxiality; plastic porously damage; porous media; brittle crush

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