摘要
采用弹塑性有限单元方法 ,通过模拟符合实际状况的逐步加载过程所引起应力场和塑性形变区的研究 ,得出如下结果 :①在塑性或韧性剪切形变情况下 ,断裂或形变带的共轭剪切角往往大于 4 5° ;②在双向挤压应力条件下 ,先存断裂的前缘部位没有拉伸应力存在 ,但可能有伸展形变发生 ;③与最大主压应力夹角为 3 0°～ 90°的断层前缘是偏应力的优势方位 ,容易发生塑性剪切形变 ,特别是夹角为 60°左右的断层是最易发生新的构造活动的断层 ;④多数断层两侧一定范围内以及断层内部是相对的低应力区。这些应力的低值区 ,非常有利于矿液和油气的运移。
Using the finite element method, this paper has studied the stress field and elastic and plastic regions around faults in different orientations under slowly loaded two dimensional pressure. The results are as follows : ①In the case of plastic or ductile deformation, conjugate shear angle of the deformation belts is usually larger than 45°;② Under the above mentioned condition there are no tensile stresses near the tip of faults, but stretch deformation is likely to occur;③Near the end of faults to be inclined at 30°～90°,especially at 60°or so to maximum principal stress,there are zones of deviatoric stress concentration. In these directions it is easier to form new shear deformation and fracture belts;④ In areas on both sides of faults and within the interior of faults, stresses are usually lower than the regional stress. In these regions the state of lower stress is favorable for the migration, accumulation and precipitation of mineral liquids and oil gas.
出处
《地球学报》
EI
CAS
CSCD
北大核心
2002年第1期11-16,共6页
Acta Geoscientica Sinica
基金
国家自然科学基金项目 ( 19972 0 64 )
国土资源部资助项目 ( 9910 0 5 )资助
关键词
断层
非线性本构关系
塑性区
有效应力
屈服应力
地质意义
fault nonlinear stress strain relationship plastic region equivalent stress yield stress
