ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Rock is a heterogeneous and anisotropic compound material, containing many shearsurfaces, cracks, weak surfaces and faults. Damage and failure in a rock mass can occur throughsliding along persistent discontinuities, or fractures. A new micromechanical approach tomodeling the mechanical behavior of excavation damaged or disturbed zone (EDZ) ofanisotropic rock is presented based on knowledge of the inhomogeneity of rock. In thisnumerical model, damage is analyzed as a direct consequence of microcracks growth. A studyof the effect of elastic and failure anisotropy plus inhomogeneity on the undergroundexcavations reveals that the modes of failure can be significantly influenced by the rockstructure on the small and large scales. Fractures that develop progressively aroundunderground excavations can be simulated using a numerical code called RFPA (RealisticFailure Process Analysis). This code incorporates the microscopic inhomogeneity in Young’smodulus and strength characteristic of rock. In the numerical models of a rock mass, values ofYoung’s modulus and rock strength are realized according to a Weibull distribution in whichthe distribution parameters represent the level of inhomogeneity of the medium. Anothernotable feature of this code is that no a priori assumptions need to be made about where andhow fracture and failure will occur – cracking can occur spontaneously and can exhibit a varietyof mechanisms when certain local stress conditions are met. These unique features have madeRFPA capable of simulating the whole fracturing process of initiation, propagation andcoalescence of fractures around excavations under a variety of loading conditions. The resultsof the simulations show that the code can be used not only to produce fracturing patterns similarto those reported in previous studies, but also to predict fracturing patterns under a variety ofloading conditions. The numerical model was able to reproduce the associated complex stresspatterns and the microseismic emission distribution for a variety of rock structural conditions
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/52/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.324-325.81.pdf
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