...) advantage is that peak strength, residual strength, and parting with the strength reduction method using the degradation rate in the post-failure region are all related developed coal mass model. to CMS through regression analyses, and the variation in CMS leads to the change in these properties of coal...

.... It was found that the elastic BBM with no provision for grain damage overpredicted the peak strengths for high confinement conditions. The introduction of inelasticity or explicit fractures within the blocks, both led to a good match in peak strengths for the entire range of confining stresses tested, although...

... contact models were used to describe the mechanical behaviors of fractures and rock matrix, then the uniaxial compressive tests were mimicked in this study. The results indicate that the peak strength of models decreases generally with the increase of fracture number, which is due to the growth...

... of peak strength and elastic properties (Young's modulus and Poisson's ratio), as measured through unconfined or confined (triaxial) testing. However, with the advent of stiff, servo-controlled loading frames able to collect accurate post-peak data during triaxial tests, it is also possible to estimate...

...-based methods were used to calculate elastic properties, peak strength, crack initiation, and crack damage. The vein-type samples were on average softer, weaker, and had lower brittle thresholds than their matrix counterparts. Variability within the vein-type samples is attributed to vein mineralogy...

... a dramatic peak strength deterioration; coal strength deterioration was exacerbated with respect to gas pressure. However, as the gas was in subcritical phase, gas density increasing induced hardening effect may be dominant; supercritical CO2 led to a strong softening on coal skeleton and resulted...

..., 2016; Hashiba et al., 2016). However, only the loading-rate dependence of peak strength has been investigated in the previous studies. Primary creep of intact rocks at low stress level is one of the time-dependent behaviors in the pre-failure region. In contrast, the rock masses around tunnels...

... are presented and linked to the macro-scale responses. The simulation results show that the strength and modulus of jointed rock masses decrease significantly due to excavation. The peak strength after excavation returns to the largest axial stress value before excavation regardless of the joint inclination...

... and has some applicability. wellbore integrity hard rock pressure sensitivity Reservoir Characterization Upstream Oil & Gas peak strength reservoir geomechanics strength failure criterion strength parameter Wellbore Design criterion marble residual strength cohesion MPa internal...

... orientation input parameter peak strength MPa Upstream Oil & Gas Simulation Lisjak georgian bay shale compression test perpendicular tunnel bedding plane Brazilian disc element size 1. INTRODUCTION Numerical modelling is an invaluable tool used to understand varying scales of complex rock...

... Abstract: Although it is recognized that the peak strength of the rock is a unique function of confining stress minus pore pressure (s 3 – P ), examples of laboratory or numerical studies that focused on investigating the effects of pore pressure on weakening or strengthening the crack...

... was observed to occur at stress differences similar to the peak strength of the shale as determined by constant strain rate triaxial tests in some samples, other samples ruptured at stress differences of only 25 to 50 percent of the expected peak strength. Introduction Fine-grained geological units...

... criteria. The peak strength of the coal-mass is evaluated ARMA 15-XXXX Numerical Simulation of Deformation and Failure Process of Coal-Mass Mohamed, K.M. Office of Mine Safety and Health Research, NIOSH, Pittsburgh, PA, USA Tulu, I.B. and Klemetti, T. Office of Mine Safety and Health Research, NIOSH...

.... The calibrated model very accurately predicts, in a quantitative sense, the macroscopic properties of real granite such as elastic properties, damage thresholds (crack initiation and interaction stresses), peak strengths (tensile and compression strengths), triaxial strength envelope (friction angle and cohesion...

... strength compression reservoir characterization end constraint uniaxial compression contact loading condition prism specimen stress-strain curve reservoir geomechanics rock specimen simulation peak strength constraint cylinder specimen post-peak behavior ideal loading condition...

... Characterization criterion residual strength peak strength Barton criteria porosity Upstream Oil & Gas compressive strength estimation residual value shear strength roughness normal stress envelope fragment friction angle strength constant friction angle particle Rockfill rock mass 1...

.... The numerical experiment results show that when modeling the rock behavior under compression, ignoring the coupled damage-flow processes results in an inaccurate prediction of mechanical properties of rock such as the peak strength and the post-peak response. The stress-strain response of the sample indicates...

... provided confinement to the rock specimens during testing. A constant deformation rate of 0.003 mm/s was used in all tests. This rate achieved peak strengths within 5 to 10 minutes of loading. Differences in elastic properties between rock and the steel loading platens used in testing were expected...

... in cohesive crack model, as shown in figure 1[1]: pchw = (1) where ch is the crack band width, and p is the inelastic fracturing strain beyond the peak strength in the crack band model. (a) (b) Fig. 1. Correspondence between cohesive crack model and crack band model: (a) cohesive crack model; (b) crack band...

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