地质作用经常是流变过程,岩石经受长时间应力作用可以在小应力条件下产生大变形。地质作用具有充分漫长的时间,所以野外露头成为研究天然流变学最好的现场,流变学理论在力学中自19世纪下半叶以来已经有迅速的发展,但用于解释地质作用的文献仍然很少。文中介绍一个基本粘弹性模型——马克斯威尔模型作为描述岩石变形的实例,同时给出应变与应力和时间三者的本构关系。代入真实岩石的“E”值和“η”值,获得了岩石的“马克斯威尔松弛时间”,约为10^12S,约合3.2万年,这意味着使应力经松弛降低到某一明显程度和使应变经蠕变增加到某一明显程度在数量级上至少需要10万年以上。
Rock deformation in earth is a typical rheological process, during which large strain could occur within rock when it suffers small stress for a long-term. Generally, outcrop of many rocks in the field could be the best examples of rheological deformation occurred during geological time. Rheology has been rapidly developed in the area of mechanics since it was established in the late 19th century. Unfortunately, only a few publications applying rheological theory to geology could be found in the literature. This paper presented an example of using a basic visco-elastic model, the Maxwell Model, to analyze rock deformation. A constitutive equation was established to describe the relationship among stress, strain and time. When using rock's real parameters of "E" and "η", it was found that its Maxwell Relax Time was about 10^12 seconds, or 3.2× 10^4 years. This indicates that it would take more than 10^5 years that the magnitude of stress relax or strain increment reaches a significant level.