糜棱岩成因的细观损伤力学模型

A meso-damage mechanical model of mylonite formation

文章提出了一个糜棱岩成因的孔洞损伤力学体胞模型。糜棱岩原岩在糜棱化过程中经历了2个主要阶段:即由流动构造引起的韧性孔洞损伤阶段和孔洞损伤所形成的多孔介质受局部低围压高轴压作用发生的韧带破碎阶段。基于该体胞模型,对一具体的糜棱岩原岩———花岗岩,用有限元法就其糜棱化全过程进行了初步模型分析和数值模拟,发现在糜棱岩产出的地应力条件下,多孔介质韧带破碎是完全可能发生的。

In order to expound some bewildering phenomena of mylonite formation, such as the plastic distortion and the brittle distortion coexisting in mylonite micro-texture, this paper proposes the meso-damage mechanical representative volume element（RVE） of mylonite parent rock. It is considered that there are two main phases during the course of mylonite parent rock mylonitization. One is the plastic porous damage phase which is caused by plastic flow, and the other is the phase of the break of crumbly ligaments which are formed during the course of porous damage. Ligaments bear high pressure in the direction of the axis and local low ambient pressure. Based on the presented meso-damage mechanical model of mylonite formation, preliminary analysis of the mylonitization course of a specific mylonite parent rock, granite, is given by the finite element method. It is found that the porous media＇scrush is very possible on the stress condition under which mylonite is formed.