Tensile Fracturing In Rocks

‘Tensile Fracturing in Rocks’ presents field observations on fracturing of sedim- tary rocks and granite outcrops from various provinces in three continents. It also combines results of recent experiments conducted at different laboratories around the world with current theories on fracturing. In treating faults, this book limits itself to faults that are associated with joint sets produced by definable causes and occasi- ally to cases where interaction between the two types of fracture – faults and joints – is not clear. The book’s subject matter is divided over six chapters, which are briefly described below. Chapter 1 summarizes current key concepts in fracture physics. It starts with a pr- entation of the elastic theory of fracture, and concentrates on the results of linear el- tic fracture mechanics. The chapter touches also upon other fracture properties, e.g., crack nucleation, dynamic fracturing and slow fracturing processes. Nucleation is - dressed by statistical mechanics methods incorporating modern approaches of th- mal and fiber bundle processes. The analyses of dynamic fracturing and slow fract- ing focus on the differences, as compared to the linear elastic approach. The cont- versy in interpreting experimental dynamic results is highlighted, as are the surface morphology patterns that emerge in fracturing and the non-Griffith crack extension criterion in very slow fracturing processes.

The analysis of crack problems through fracture mechanics has been applied to the study of materials such as glass, metals and ceramics because relatively simple fracture criteria describe the failure of these materials. The increased attention paid to experimental rock fracture mechanics has led to major contributions to the solving of geophysical problems. The text presents a concise treatment of the physics and mathematics of a representative selection of problems from areas such as earthquake mechanics and prediction, hydraulic fracturing, hot dry rock geothermal energy, fault mechanics, and dynamic fragmentation.

Scientific understanding of fluid flow in rock fracturesâ€"a process underlying contemporary earth science problems from the search for petroleum to the controversy over nuclear waste storageâ€"has grown significantly in the past 20 years. This volume presents a comprehensive report on the state of the field, with an interdisciplinary viewpoint, case studies of fracture sites, illustrations, conclusions, and research recommendations. The book addresses these questions: How can fractures that are significant hydraulic conductors be identified, located, and characterized? How do flow and transport occur in fracture systems? How can changes in fracture systems be predicted and controlled? Among other topics, the committee provides a geomechanical understanding of fracture formation, reviews methods for detecting subsurface fractures, and looks at the use of hydraulic and tracer tests to investigate fluid flow. The volume examines the state of conceptual and mathematical modeling, and it provides a useful framework for understanding the complexity of fracture changes that occur during fluid pumping and other engineering practices. With a practical and multidisciplinary outlook, this volume will be welcomed by geologists, petroleum geologists, geoengineers, geophysicists, hydrologists, researchers, educators and students in these fields, and public officials involved in geological projects.

This book presents a new fracturing technique that should be considered as a potential alternative, or a companion technique, to hydraulic fracturing of tight gas reservoirs and low permeability rock masses. As opposed to hydraulic fracturing which generates a few numbers of large cracks, electro-hydraulic fracturing induces diffuse micro-cracking and fragmentation of rocks. Laboratory tests demonstrate that increases of permeability by two orders of magnitude can be reached, without major cracking in tested specimens. This book discusses the principles of this new technique, reports experiments which have been developed is order to prove the concept and finally describes the numerical model from which the potentialities of this technique in representative reservoir conditions can be assessed.

This text comprises different basic aspects of brittle failure for rocks. It considers classical and contemporary models, as well as failure patterns under different loading schemes.

Rock fractures control many of Earth's dynamic processes, including plate-boundary development, tectonic earthquakes, volcanic eruptions, and fluid transport in the crust. An understanding of rock fractures is also essential for effective exploitation of natural resources such as ground water, geothermal water, and petroleum. This book combines results from fracture mechanics, materials science, rock mechanics, structural geology, hydrogeology, and fluid mechanics to explore and explain fracture processes and fluid transport in the crust. Basic concepts are developed from first principles and illustrated with worked examples linking models of geological processes to real field observations and measurements. Many additional examples and exercises are provided online, allowing readers to practise formulating and quantitative testing of models. Rock Fractures in Geological Processes is designed for courses at the advanced undergraduate and graduate level but also forms a vital resource for researchers and industry professionals concerned with fractures and fluid transport in the Earth's crust.