... properties at the time of fracture formation for each case. The subcritical crack index, mechanical layer thickness, total strain and strain rate are all likely controls over the relative proportion of narrow to wide fractures in a population. 2. GEOLOGIC SETTING OF FRACTURE SETS The fracture sets examined...

... was undertaken to examine the process of fracturing of the roof strata that follows the longwall advancement. Many factors influence support weighting [1], the most important of which include: seam thickness bulking characteristics of immediate roof cover depth and abutment stress strength...

... Reservoir Characterization Berea sandstone Simulation hydraulic fracturing fracture mechanics structural geology strength fracture toughness cementation Upstream Oil & Gas Thickness sandstone specimen Rock mechanics Symposium weakly notch length fracture toughness test...

... discontinuities, such as gneissic fabric, shear planes or even sedimentary bedding joints. These dominant rock structures extend continuously, effectively separating the rock mass into strata, often of similar thickness, typically from a few to tens of centimeters. In the case of metamorphic, fault-displaced...

... tunnel 3 borehole specimen reservoir geomechanics Thickness marl investigation Reservoir Characterization support structure tunnel lining turmel Drilling observational method theoretical result lining permeablity girder Upstream Oil & Gas information diameter tunnel 1...

... boreholes reveal that the average coal stress increases with the average rock stress. Upstream Oil & Gas seam Thickness Coal Basin MPa database stress difference tectonic stress Reservoir Characterization coal horizontal stress sequence seam thickness stiffness Rock stress minimum...

... the cave. The beds within the cave and to 'a substantial distance above are 9lean limestones of low porosity that have similar me- chanical properties. Of greater imp0l1ance than lithology are the bedding plane joints that separate the roof into plates of varying thickness. 3 ANALYSIS OF ROOF F t.\lLURE...

... density. This equation provides the stress distribution at the edge of a theoreticallongwall panel where: (I) the coal seam and overburden are all one elastic material, (2) the width of the panel is negligible in comparison to the depth, and (3) the thickness of the seam is negligible in comparison...

... Characterization Thickness assessment application rock mass probability Surface Crown Pillar pillar span concept Pacific Rocks 2000, Girard, Liebman, Breeds & Doe (eds) © 2000 Balkema, Rotterdam, ISBN 90 5809 1554 An update on the scaled span concept for dimensioning surface crown pillars for new...

... significant if the joints are 10- close enough to each other so that the spacing is comparable to the layer thickness or smaller than the latter. To the best of our knowledge, rigorous closed form solutions of such problems are not available even for two joints (unless thev are lo- cated along a straight line...

... shotcrete thickness Thickness rock support system excavation underground excavation support pressure Japan ABSTRACT ABSTRACT: Rock support system design practices for large-scale underground excavations in North America, Europe, Japan and some other countries are reviewed in a systematic...

... for determination of the law of variation of the yield stress with depth from data is outlined. A flow-no flow criterion is formulated. It is shown that the model predicts well the depth at which shear flow initiates and the thickness of the shear zone. All parameters involved in the visco-plastic model...

... that can estmate chain pillar loads for weak floor conditions based on LGM simulation results. Meanwhile, based on the thickness and the modulus of elasticity of weak floor atrata, the developed models estimate Bearing Capacity (UBC) of weak floor strata. It also accounts the effect of adjacent pillar...

... Aydan Artificial Intelligence Thickness discontinuity Upstream Oil & Gas numerical analysis stability configuration displacement rock slope Contact Element finite element method mpa mpa mpa mpa rock mass interface discrete finite element method block property Rock Mechanics...

..., and with each layer having the identical elastic modulus, Poisson's Ratio, and thickness. This formulation does not require specific material properties for each individual layer, and yet it still provides a realistic suppleness to the overburden that is not possible with the classic, homogeneous isotropic...

... indicates that fracture permeability normal to stratification is a function of: (1) the fracture spacings; (2) layer thickness; (3) fracture apertures in each layer; (4) the layer interface (bedding plane) aperture; and (5) the product of fracture spacings of adjacent beds. An example is given in which...

... stability analysis shallow stope rock mass case study metals & mining Thickness Ground Control span Surface Crown Pillar Rock Mechamcs, Aubertm, Hassam &Mitn (eds) ¸ 1996 Balkerna, Rotterdam. ISBN 90 5410 838 X Lessons learned from stability analysis of case studies of shallow stopes of hard...

... & Gas fracture toughness hydraulic fracturing Thickness bit design deeper fracture experiment specimen rebinder surfactant fracture surface-active chemical agent mechanically chip thickness damage zone bit selection fracture length rock drilling shallow surface crack Drilling...

... in the shale/marl members, and exhibit a spacing about equal to brittle-bed thickness. Laboratory experiments involving the propagation of a mode 1 fracture in a brittle layer toward a clay layer at 10 and 50 MPa confining pressures indicate that fracture containment in the brittle layer is enhanced...

... by certain combinations of interacting initial cracks. Thickness experiment Cherepanov crack propagation Dyskin hydraulic fracturing free surface boundary uniaxial compression tensile crack arrangement mechanism crack growth straight crack Germanovich initial crack toughness...