Journal ArticleDOI
Hydraulic characteristics of rough fractures in linear flow under normal and shear load
H. S. Lee,T. F. Cho +1 more
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In this article, a hydraulic testing system was built to investigate the hydraulic behavior of rough tension fracture, which is capable of measuring both the flow rates and the normal and shear displacement of a rock fracture.Abstract:
A hydro-mechanical testing system, which is capable of measuring both the flow rates and the normal and shear displacement of a rock fracture, was built to investigate the hydraulic behaviour of rough tension fractures. Laboratory hydraulic tests in linear flow were conducted on rough rock fractures, artificially created using a splitter under various normal and shear loading. Prior to the tests, aperture distributions were determined by measuring the topography of upper and lower fracture surfaces using a laser profilometer. Experimental variograms of the initial aperture distributions were classified into four groups of geostatistical model, though the overall experimental variograms could be well fitted to the exponential model. The permeability of the rough rock fractures decayed exponentially with respect to the normal stress increase up to 5 MPa. Hydraulic behaviours during monotonic shear loading were significantly affected by the dilation occurring until the shear stress reached the peak strength. With the further dilation, the permeability of the rough fracture specimens increased more. However, beyond shear displacement of about 7 to 8 mm, permeability gradually reached a maximum threshold value. The combined effects of both asperity degradation and gouge production, which prohibited the subsequent enlargement of mean fracture aperture, mainly caused this phenomenon. Permeability changes during cyclic shear loading showed somewhat irregular variations, especially after the first shear loading cycle, due to the complex interaction from asperity degradations and production of gouge materials. The relation between hydraulic and mechanical apertures was analyzed to investigate the valid range of mechanical apertures to be applied to the cubic law.read more
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Journal ArticleDOI
A review of techniques, advances and outstanding issues in numerical modelling for rock mechanics and rock engineering
TL;DR: In this paper, the authors present the techniques, advances, problems and likely future developments in numerical modelling for rock mechanics and discuss the value that is obtained from the modelling, especially the enhanced understanding of those mechanisms initiated by engineering perturbations.
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Aftershocks driven by a high-pressure CO2 source at depth.
Stephen A. Miller,Cristiano Collettini,Lauro Chiaraluce,Massimo Cocco,Massimiliano Rinaldo Barchi,Boris Kaus +5 more
TL;DR: It is proposed that aftershocks of large earthquakes in such geologic environments may be driven by the coseismic release of trapped, high-pressure fluids propagating through damaged zones created by the mainshock, which may provide a link between earthquakes, aftershock, crust/mantle degassing and earthquake-triggered large-scale fluid flow.
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Changes in fisheries discard rates and seabird communities
Stephen C. Votier,Robert W. Furness,Stuart Bearhop,Stuart Bearhop,Jonathan E. Crane,Richard W. G. Caldow,Paulo Catry,Kenny Ensor,Keith C. Hamer,Anne V. Hudson,Ellen Kalmbach,Nicholas Klomp,Simone Pfeiffer,Simone Pfeiffer,Richard A. Phillips,Isabel Prieto,David R. Thompson +16 more
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Journal ArticleDOI
Stress effects on permeability in a fractured rock mass with correlated fracture length and aperture
Alireza Baghbanan,Lanru Jing +1 more
TL;DR: In this paper, the effect of stress on permeability and fluid flow patterns in fractured rock masses was studied when distributed fracture aperture is correlated with fracture trace length, using a discrete elemen.
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An investigation of stimulation mechanisms in Enhanced Geothermal Systems
Mark W. McClure,Roland N. Horne +1 more
TL;DR: In this article, the authors review ten historical EGS projects and find that typically, flow from the wellbore is from preexisting fractures, bottomhole pressure exceeds the minimum principal stress, and pressure-limiting behavior occurs.
References
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Book
Statistics and data analysis in geology
TL;DR: In this article, a thoroughly revised edition presents important methods in the quantitative analysis of geologic data, such as probability, nonparametric statistics, and Fourier analysis, as well as data analysis methods such as the semivariogram and the process of kriging.
Journal ArticleDOI
The shear strength of rock joints in theory and practice
Nick Barton,V. Choubey +1 more
TL;DR: In this paper, the authors describe an empirical law of friction for rock joints, which can be used both for extrapolating and predicting shear strength data, and demonstrate that it can be estimated to within ± 1° for any one of the eight rock types investigated.
Journal ArticleDOI
Fundamentals of rock joint deformation
TL;DR: In this article, the deformation characteristics of rock joints under normal and shear loading were investigated by conducting loading/unloading and repeated load cycling tests on a wide variety of fresh and weathered joints in five different rock types.
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Variowin: Software for Spatial Data Analysis in 2D
TL;DR: This pack provides Windows software for analyzing spatial data and graphical tools for variogram surfaces, directional variograms, h-scatterplots and variogram clouds that enable researchers in spatial statistics and geostatistics to interactively analyze and model the spatial continuity of spatial data.
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