Normal Wedge Indentation in Rocks with Lateral Confinement   总被引：3，自引：2，他引：1  

H. Huang  B. Damjanac  E. Detournay 《Rock Mechanics and Rock Engineering》1998,31(2):81-94

Summary The paper reports results of a numerical analysis of the wedge indentation problem. The main objective of this research is to investigate the influence of the lateral confining stress on the development of the plastic zone under the indenter and on the initiation of tensile fractures. Numerical analysis indicates that the location of maximum tensile stress (interpreted as the point of crack initiation) moves away from the indentation axis as the lateral confinement increases. It is found that a small increase in the confining stress from zero induces a large increase in the inclination of this point on the indentation axis. However, the confinement does not reduce significantly the maximum tensile stress and it hardly influences the indentation pressure. These numerical results shed some light on the mechanism of formation of lateral or sub-horizontal tensile cracks observed in the indentation experiments.  相似文献   

Evidence for a Long-Term Strength Threshold in Crystalline Rock   总被引：3，自引：1，他引：2  

Branko Damjanac  Charles Fairhurst 《Rock Mechanics and Rock Engineering》2010,43(5):513-531

The mechanical response of brittle rock to long-duration compression loading is of particular concern in underground disposal of nuclear waste, where radionuclides must be isolated from the biosphere for periods of the order of a million years. Does the strength decrease without limit over such time, or is there, for some rock types, a lower “threshold” strength below which the rock will cease to deform? This paper examines the possibility of such a threshold in silicate crystalline rocks from several perspectives, including: (1) interpretation of the results of short-term creep tests on rock; (2) numerical analysis of the effect of decrease in fracture toughness due to stress corrosion on the strength of a crystalline rock; and (3) evidence from plate tectonics, and observations of in situ rock stress in granite quarries. The study concludes that there is clear evidence of threshold strength. The threshold is of the order of 40% of the unconfined compressive strength or higher for laboratory specimens under unconfined compressive loading, and increases rapidly in absolute value with confinement. Field evidence also leads to the conclusion that the long-term strength of crystalline rock in situ is of comparable magnitude to the laboratory value.  相似文献   

Effect of fault reactivation on deformation of off-fault fractures near a generic deep geological repository in crystalline rock in Canada     

Blanksma  Derrick  Hazzard  Jim  Damjanac  Branko  Lam  Tom  Kasani  Hossein A. 《Journal of Seismology》2022,26(5):987-1002

Journal of Seismology - In this study, fault rupture and its effect on the deformation of the off-fault fractures are numerically simulated. The purpose of the analysis is to determine the distance...  相似文献