Abstract: En echelon shear rupture zone is of a common type of ruptures in the crust. Several models which contain one,two and three fanlts arranged in en echelon arrays are calculated by twe-dimensional finite element method. The result indicates that a shear rupture zone acts just as a single shear fault in kinematics. There exist tensile and compressive areas at both ends of a shear rupture zone. They are the products of the relative movement of two blocks along the shear rupture zone. The structure of rock bridge (pullapart basin or push-upward) and the meterial mechanical coefficient are two main factors affecting the concentration of the tensile and compressive stresses at the ends of a shear rupture zone. Moreover,the structural features and faulting types in tensile and compressible areas are discussed in the paper.

Key words: Shear rupture zone, Tensile or compressive area, Finite element simulation, Stress concentration

摘要： 本文利用二维有限元方法计算了由一条、二条和三条不连续的羽列断层组成的多组剪切破裂带模型。研究表明,不连续剪切破裂带在运动学性质上与单一剪切断层相类似,存在着作为剪切破裂带整体尾端的张、压性四象限分布的现象,它们是强相互作用的岩桥区物质发生变形弱化,剪切破裂带两侧块体作相对运动在尾端的调整产物;岩桥区的构造力学性质和物质的材料力学参数是影响剪切破裂带尾端张、压性区应力集中程度和范围大小的两个重要因素。最后结合实例讨论了张、压性区的构造特征和破裂方式。

关键词: 剪切破裂带, 尾端张、压性区, 有限元模拟, 应力集中