... Abstract Under high stress conditions, rock bursts, borehole breakouts, and spalling events are common phenomena that occur around underground openings. In general, together these three phenomena represent brittle failures of an intact rock mass; however, individually they reflect different...

... behavior falls somewhere between brittle and ductile range. The theory of brittle failure is based on crack growth which usually initiate at stresses much lower than its Uniaxial Compressive Strength (UCS) (Diederichs1999). According to Martin (1994), this level is at one-third to one- fourth of UCS. Also...

... laboratory results, field calibration and field monitoring data of both active and inactive failure processes. frequency cavern brittle failure chalk Reservoir Characterization spike incipient instability nanoseismic monitoring classification shallow cavern detection instability seismic...

... machine utilization factor Steg lateral adit blocky ground reservoir geomechanics boreability construction TBM performance Upstream Oil & Gas rock mass Lötschberg Base Tunnel qualitative evaluation Kaiser cutterhead Reservoir Characterization Downtime brittle failure...

... Upstream Oil & Gas damage growth plane excavation structural geology deep geological environment experiment creep reservoir geomechanics brittle failure Inada granite differential stress granite time-dependent damage growth Reservoir Characterization wave velocity tertiary...

... In this paper some failure phenomena observed in the crossing of brittle rock formations at the Lötschberg base tunnel are presented. A brittle failure criteria, recently developed by Canadian researchers, is applied through finite element calculations together with a semi-empirical failure...

... localization tensile stress excavation compression stress distribution fracture numerical model hydraulic fracturing quartzite disc brittle failure specimen brittle rock fracture formation deformation Fractur~ng of brftle rock under compression: Cause and effects in large quartzite discs...

... ABSTRACT: In the paper is presented a new linear strength criterion with the assumption that (i) decisive about the brittle failure of rock material are both the shearing stresses and the normal tensile stresses, (ii) in a clastic material, the tensile stresses may be evoked also when...