... on their strength anisotropy. In the article, the anisotropy of a mechanical property, i.e. the fracture toughness, of migmatized gneiss is discussed. For this purpose, series of semi-circular bend tests were carried out on specimens of migmatized gneiss with a metamorphic foliation. The methodology used...

... geomechanical properties of rocks such as tensile strength (σ t ) and mode I fracture toughness ( K IC ). To validate the indirect tensile test by using the complete Brazilian disc, the crack must be initiated from the central region of the specimen, and the loading angle that corresponds to the arc...

... Abstract The objective of this study is to examine any variation from micro to macro scale mode-I fracture toughness of granite using micro-sized specimen and semi-circular specimen. The rock used in the tests is Iksan granite (Korea) which is composed of minerals, such as plagioclase...

... Abstract It is essential to understand the mode I fracture toughness of rock under in situ conditions found underground, such as confining pressure, for assessment of the stability of underground rock structures. Some researchers have performed several types of fracture toughness tests...

... ABSTRACT: Microfractures and discontinuities are the common structural features of the rock mass lead initiating and developing the brittle fractures in rocks. Fracture toughness is an intrinsic material property for the pre-exist cracks initiate fracture development and play a significant...

... ABSTRACT: Mode I fracture toughness was determined under confining pressure for various rock types using sleeve fracturing laboratory experiments. In these experiments, a confining pressure was applied to rock cores with central axial boreholes. A polymer sleeve was pressurized inside...

... ABSTRACT: A brittle fracture of rocks occurs under subjected stress state. What parameters govern fracture in rock? It is considered that the fracture is dependent on not only distribution, orientation, size, shape and deformability of grains but also fracture toughness of grains and grain...

... were carried out using MTS rock test system with a loading rate of 0.002 mm/sec. Mean value of mode II fracture toughness of granite showed 2.33 MPa m 0.5 . Mode I toughness of the same granite was 1.12 MPa m 0.5 , determined by Brazilian disk test and K IIC /K IC = 2.08. The smooth fracture...

... Abstract Anisotropy of the physical properties such as elastic wave velocity, elastic modulus, strength, and fracture toughness of rocks should be understood to design and construct rock structures and estimate its stability. To investigate anisotropy in mode I fracture toughness ( K Ic...

... with uniaxial compressive strength; at larger depth of cut, brittle failure is dominant and the fracture toughness control the force responses. This study aims at assessing the strength within the ductile-mode cutting and the fracture toughness within brittle failure via rock scratching tests. First, we apply...

... Design reservoir geomechanics hydraulic fracturing injection pressure Upstream Oil & Gas fracture growth borehole SF experiment breakdown pressure ff experiment fracture length fracture mechanical evaluation diameter wellbore integrity stress intensity factor fracture toughness...

... Abstract The Cracked Chevron Notch Brazilian Disc (CCNBD) method has been used to determine rock fracture toughness value of rocks in rock mechanics since many years. The CCNBD method has advantages over the other proposed fracture toughness tests in terms of the simplicity of sample...

... hydraulic fracturing image correlation determination crack propagation reservoir geomechanics Rock mechanics geometry evolution Reservoir Characterization fracture toughness evaluation experimental result Upstream Oil & Gas mixed mode experimental evaluation CCBD propagation...

... (Ouchterlony, 1988), the cracked chevron notched Brazilian disc (CCNBD) method (Fowell, 1995), and notched semi-circular bending (NSCB) method (Kuruppu et al., 2013), for the determination of quasistatic fracture toughness. However, the studies on fracture behaviours under dynamic loading have been less...

.... Earlier measurements of rock fracture toughness followed the ASTM-E399 stan- dard method. Because most rock are brittle, fatigue pre-cracking required in ASTM standard has been found to be very difficult to produce (Chen, Pan & Amadei 1998). To solve rock fracture problems, The International Society...

... fracturing CCNBD specimen failure load foliation-loading angle phyllite Reservoir Characterization fracture core sample anisotropic brisbane phyllite fracture toughness tensile foliation plane splitting anisotropy Brisbane phyllite tensile strength Rock Mechanics for Resources, Energy...

... to investigate the influence of the surrounding water vapor environment on uniaxial compressive strength, tensile strength and fracture toughness. The rocks used in this paper were Kumamoto andesite, African granodiorite and Korean granite. It was made clear that rock strengths and fracture toughness...

... Artificial Intelligence fracture mechanics stress intensity factor variation initiation Upstream Oil & Gas fracture toughness borehole crack tip mechanics propagate fracture initiation propagation hydraulic fracturing energy release rate crack length eurock 2012 linear...

... Abstract: This study presents the results of laboratory diametrical compression tests performed on Brisbane tuff disc specimens to investigate their mode-I fracture tough-ness response to static and cyclic loading, as a function of the applied load. Fracture toughness (KIC) is an important...

... Abstract: A novel outcome of the research described is the observation of the effect of indirect tensile cyclic loading on the fracture toughness of rocks. The mode I fracture toughness (KIC) response to indirect tensile cyclic loading was found to be different from that under static loading...