![]() There is number of fracture propagation criteria provided by the theory of linear elastic fracture mechanics (LEFM), originally developed for metals. Modeling the initiation and propagation of fractures in continuum solids with stress analysis requires the use of a criterion that will dictate if the fracture tip is at the state to advance further. Some other applications in geomechanics involving fracturing include the magma-driven fractures ( Spence and Turcotte, 1985), the preconditioning of rock masses in mining operations to promote caving ( Jeffrey et al., 2001), the formation of barriers to stop contaminant transport in environmental projects ( Murdoch and Slack, 2002), the reinjection of drilling cuttings ( Moschovidis et al., 2000), the heat production from geothermal reservoirs ( Legarth et al., 2005), and, more recently, the risk of induced fractures in CO 2 deep geological storage ( Papanastasiou et al., 2016). The most notable example is hydraulic fracturing, a technique widely used in the petroleum industry to enhance the recovery of hydrocarbons from underground reservoirs. There are also a number of engineering applications in Geomechanics, not related to safety of structures, where fractures are induced or naturally occurred. Panos Papanastasiou, Ernestos Sarris, in Porous Rock Fracture Mechanics, 2017 6.1 IntroductionĬrack initiation and propagation is encountered in many engineering disciplines that involves advanced loading stages of mechanical behavior of solids and structures that may lead to failure. CRACK THEORY HABIBIE CRACKThe theory predicts that a crack will propagate in order to lower the total energy of the system, by dissipating the elastic strain energy due to loading into the creation of a new surface. Crack propagation may be described using the energy criterion theory ( Griffith, 1920) which is based on thermodynamic and energy balance. Fracture occurs when the applied stress is sufficient to break the atomic bonds of the solid ( Anderson, 1995 Scholz, 2002). To study fracture mechanics, three important variables have to be taken into account: the applied stress, the size of the initially present flaw, and the fracture toughness ( Anderson, 1995). ![]() A short review of the fundamentals of crack propagation in linear elastic material is given, followed by a discussion on the effects of environmental conditions on propagation velocity. Crack propagation may occur at low stress and is usually characterized by a slow propagation, so it is often referred to as subcritical crack propagation or stress corrosion. ![]() ![]() However, as it will be presented here, slow crack propagation in rocks is affected by the environment and the fluid chemistry and can be seen as mechanical phenomenon facilitated by chemical effects. Jean-Pierre Gratier, in Advances in Geophysics, 2013 3.2.1.2 Subcritical Crack PropagationĬrack propagation is described using fracture mechanics theory and would therefore have its place in the mechanical compaction section. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |