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The fact that a variety of phenomena in the behavior of metals, concrete, and rock can be traced back to a few simple physical concepts goes to show that these concepts are not without real physical foundation. When considering the results of tests on rocks particular forms of hysteresis loops may be encountered, which can only be adequately explained in terms of a combination of the wedge friction elements introduced here. The adaptation of this element takes into account the combined effect of a complex stress state and friction on a microscopic scale in a composite material like rock. Its adequateness suggests that stress de-pendent friction resistance prevails in such materials but not in metals. The micromechanical models developed here should not be understood as constitutive laws in the strict sense. They help us to understand better the physical background of the process of deformation and failure in different types of materials. It is, however, necessary to consider both the loading curve and also the unloading and reloading curves as well. Cyclic loading reveals not only secondary phenomena but also basic ones.
Index Terms:rock; TunnelingGroup
Further Information:Date published: 1979