Flexural Slip Model of Buckling Folds －Numerical Simulation & Analysis
Date Issued
2007
Date
2007
Author(s)
Jeng, Tian-Yao
DOI
zh-TW
Abstract
The flexural slip folding of buckling folds is studied based on numerical analyses. In previous studies, the elastic theoretical solutions of single layer and multilayer folds have been formulated. However these analytical solutions are based on simplifications. Some of the geological structures in the field, such as the hinge cavity of folds and the slickenside formed by flexural slip folding are still awaiting for further exploration regarding the mechanism. In this research, elasto-plastic material was adopted in numerical simulation and compared with the elastic theoretical solution. The influence of flexural slip folding on folds is then discussed as well. In the end, simulation of the large deformation behavior of folds was conducted by using bonded particle model.
The results of study show that: For an unconstrained elasto-plastic layer under compression, the wavelength can be shortened in post-buckling stage. As to folds with decaying amplitude, the elasto-plastic behavior leads to an early buckle folding and shortens the wavelength.
The appearance of cavity results in reduction of the reactive force exerted by the matrix and increases the low-frequency wavelength; on the other hand, the interface friction can counteract the effect.
The flexural slip model of multilayer folds compares well with the theoretical solution by Currie et al. (1962). For multilayer folds, the interface friction tends to increase the high-frequency wavelength and shorten the low-frequency wavelength. Cavity and interface friction tend to increase the amplitude of fold.
From the simulation of fold growth by bonded particle model, it can be divided into four stages：1. Initial compression stage; 2. Circular fold yielded and cavity was formed; 3. The plastic hinge was formed, then circular fold turned into chevron folds; and 4. The folds were flattened and the cavity was filled with matrix.
Subjects
尖頂褶皺
曲滑作用
挫屈
彈塑性
界面性質
數值模擬
chevron fold
flexural slip
buckle
elasto-plastic
interface properties
numerical simulation
Type
thesis
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