一种模拟韧性剪切带中椭球状标志体运动、变形的新方法

A new method for simulation of elliptic marker movements and deformation in ductile shear zones

韧性剪切带中赋存的椭球状应变标志体(砾石、碎斑等)是研究剪切带运动学、动力学的重要应变标志体。传统研究中椭球状标志体通过对野外露头的观测或与实验岩石学结合,判断剪切带运动方向、探讨运动学和流变学特征。随着数值模拟技术在韧性剪切带中的引入和推广,国内外许多学者试图恢复椭球状标志体的运动轨迹和变形特征,并取得了显著的成果。然而,国内文献对于模拟韧性剪切带椭球状标志体的定量及模拟研究甚少,研究方法也鲜为介绍。基于此,针对韧性剪切带中椭球状标志体变形的最新研究进展,详细介绍建立在Jeffery理论和Eshelby理论之上的数值模拟思路和方法,并利用Mathcad软件模拟了给定条件下的椭球状标志体的运动轨迹、变形特征。

The existence of the elliptic markers such as gravels and porphyroclasts in ductile shear zones is an important strain symbol in the study of kinematics and dynamics in the shear zone. The directions of shear zone movements are estimated and the characteris- tics of kinematics and rheology are discussed though the observation of field outcrop in combination with experimental petrology in traditional elliptic marker researches. With the introduction and promotion of numerical simulation techniques such as Ansys, Maflab and Mathcad in ductile shear zones, many researchers in China have tried to recover the elliptic marker movement trajectory and de- formation characteristics, and achieved remarkable results. However, methods for simulation of elliptic marker movements as well as quantitative and simulative researches on ductile shear zones have been scarcely mentioned in domestic literature. Therefore, on the basis of the latest researches on elliptic marker deformation in ductile shear zones, the paper presents the ideas and methods of numeri- cal simulation in details based on Jeffery and Eshelby＇ s theory. In addition, the authors have simulated the rotating track and deformation characteristics of elliptic markers under given conditions by using Mathcad software.