Brittle‐ductile coupling: Role of ductile viscosity on brittle fracturing
Brittle‐ductile coupling: Role of ductile viscosity on brittle fracturing
复制标题
脆性耦合：延性粘度对脆性断裂的作用
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
P. Davy
中科院分区：
文献类型：
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作者：
Sylvie Schueller;F. Gueydan;P. Davy
大陆岩石圈的局部或分布变形被认为是由流变对比引起的，特别是由脆性-韧性耦合引起的。采用平面应变二维有限元模型研究了韧性层在脆性层中从局部断裂到分布断裂转变过程中的力学作用。耦合是通过缩短由两个延性层包围的Von Mises弹性-粘-塑性层来实现的。通过将韧性层的黏度增加一个数量级，脆性层的压裂模式从局部（少断层）发展到分布（多断层），定义了黏度依赖的压裂模式。这种脆性-韧性耦合可以用韧性层对断层运动的粘性阻力来解释，这限制了连接到韧性界面的任何断层的最大位移速率。因此，粘度的增加将产生必要的新断层成核，以适应边界缩短率。
Localized or distributed deformations in continental lithosphere are supposed to be triggered by rheological contrasts, and particularly by brittle‐ductile coupling. A plane‐strain 2D finite‐element model is used to investigate the mechanical role of a ductile layer in defining the transition from localized to distributed fracturing in a brittle layer. The coupling is performed through the shortening of a Von Mises elasto‐visco‐plastic layer rimed by two ductile layers. By increasing the viscosity of the ductile layers by only one order of magnitude, the fracturing mode in the brittle layer evolves from localized (few faults) to distributed (numerous faults), defining a viscosity‐dependent fracturing mode. This brittle‐ductile coupling can be explained by the viscous resistance of the ductile layer to fault motion, which limits the maximum displacement rate along any fault connected to the ductile interface. An increase of the viscosity will thus make necessary new faults nucleation to accommodate the boundary shortening rate.