Dynamic Tensile Failure in Rocks PDF Download
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Author: Donald A. Shockey
Publisher:
ISBN:
Category :
Languages : en
Pages : 72
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Book Description
A simple homogeneous rock, Arkansas novaculite, was chosen for dynamic tensile failure studies. Experimental techniques for performing dynamic tensile tests on rocks were developed and used to provide meaningful measurements of dynamic tensile strength. A way to eliminate the occurrence of undesirable radial cracking of the specimen during testing was found; specimen recovery and fracture analysis methods were implemented. Novaculite specimens were characterized with respect to static and dynamic fracture strength, fracture toughness, defect and microstructure, and other properties and parameters pertinent to the fracture behavior. (Author).
Author: Donald A. Shockey
Publisher:
ISBN:
Category :
Languages : en
Pages : 72
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Book Description
A simple homogeneous rock, Arkansas novaculite, was chosen for dynamic tensile failure studies. Experimental techniques for performing dynamic tensile tests on rocks were developed and used to provide meaningful measurements of dynamic tensile strength. A way to eliminate the occurrence of undesirable radial cracking of the specimen during testing was found; specimen recovery and fracture analysis methods were implemented. Novaculite specimens were characterized with respect to static and dynamic fracture strength, fracture toughness, defect and microstructure, and other properties and parameters pertinent to the fracture behavior. (Author).
Author:
Publisher:
ISBN:
Category : Fracture mechanics
Languages : en
Pages : 51
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Book Description
The results of a two-year program on dynamic fracture behavior of rocks are described. The goal was to develop the capability to predict the fragment size distribution of rock resulting from known dynamic loads. This goal has been largely realized for a simple, well-characterized rock type, Arkansas novaculite, under one-dimensional-strain impact loading. A gas gun was used to accelerate flat plates against flat rock specimens. Ytterbium piezoresistive stress gages were used to measure stress histories, and the dynamic tensile strength and fragment size distributions were determined. The mechanism of fragmentation was deduced from fractographic observations on impacted specimens. (Modified author abstract).
Author: Bangbiao Wu
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Tensile failure of rocks is a main problem in underground engineering applications, where rocks are subjected to dynamic loadings while under in situ stresses. When disturbed by dynamic loads from blasting or seismicity, underground structures are vulnerable to tensile failure. Therefore, it is of great importance and thus the aim of this thesis to investigate the dynamic tensile failure of rocks subjected to underground in situ stresses, experimentally and theoretically. For the experimental study, the split Hopkinson pressure bar (SHPB) system is modified and developed with a hydraulic press for the dynamic tests under different in situ stress states. The Brazilian disc specimens made from Canadian Laurentian granite are first subjected to a prestress simulating in situ stress (including pre-tension, hydrostatic confinement, and triaxial stress state) and then loaded dynamically using the modified SHPB. For each stress state, several groups of tests are conducted under different levels of prestress and loading rate. The result shows that for all of the tests, the dynamic tensile strength increases with loading rate, revealing the so called rate dependency, which is common for engineering materials. The dependence of the dynamic tensile strength on different prestress conditions are also examined. For the theoretical study, the Dominant Crack Algorithm (DCA) is adopted to model the dynamic tensile failure of rock under different prestress states, with the non-linear regression method Particle Swarm Optimization (PSO). The modeling parameters are obtained using the PSO method based on the experimental results and the DCA modeling is carried out accordingly under the simulated prestress and loading rate. The results demonstrate the applicability of the model as the error is less than 5% with reasonable values of the parameters. These experimental results and the calibrated theoretical model will be of great importance in the design and safety of underground rock engineering projects.
Author: N. Morozov
Publisher: Springer Science & Business Media
ISBN: 3540697128
Category : Science
Languages : en
Pages : 107
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Book Description
In this book a new phenomenological approach to brittle medium fracture initiation under shock pulses is developped. It provides an opportunity to estimate fracture of media with and without macrodefects. A qualitative explanation is thus obtained for a number of principally important effects of high-speed dynamic fracture that cannot be clarified within the framework of previous approaches. It is possible to apply this new strategy to resolve applied problems of disintegration, erosion, and dynamic strength determination of structural materials. Specialists can use the methods described to determine critical characteristics of dynamic strength and optimal effective fracture conditions for rigid bodies. This book can also be used as a special educational course on deformation of materials and constructions, and fracture mechanics.
Author: Lloyd O. Bacon
Publisher:
ISBN:
Category : Rock mechanics
Languages : en
Pages : 30
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Book Description
Author: Jianchun Li
Publisher: CRC Press
ISBN: 1000883248
Category : Technology & Engineering
Languages : en
Pages : 784
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Book Description
Rock Dynamics: Progress and Prospect contains 153 scientific and technical papers presented at the Fourth International Conference on Rock Dynamics and Applications (RocDyn-4, Xuzhou, China, 17-19 August 2022). The two-volume set has 7 sections. Volume 1 includes the first four sections with 6 keynotes and 5 young scholar plenary session papers, and contributions on analysis and theoretical development, and experimental testing and techniques. Volume 2 contains the remaining three sections with 74 papers on numerical modelling and methods, seismic and earthquake engineering, and rock excavation and engineering. Rock Dynamics: Progress and Prospect will serve as a reference on developments in rock dynamics scientific research and on rock dynamics engineering applications. The previous volumes in this series (RocDyn-1, RocDyn-2, and RocDyn-3) are also available via CRC Press.
Author: D. E. Grady
Publisher:
ISBN:
Category : Fracture mechanics
Languages : en
Pages : 60
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Book Description
Author: Chun'An Tang
Publisher: CRC Press
ISBN: 0415498511
Category : Technology & Engineering
Languages : en
Pages : 366
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Book Description
When dealing with rock in civil engineering, mining engineering and other engineering, the process by which the rock fails under load should be understood, so that safe structures can be built on and in the rock. However, there are many ways for loading rock and rock can have a variety of idiosyncracies. This reference book provides engineers and researchers with the essential knowledge for a clear understanding of the process of rock failure under different conditions. It contains an introductory chapter explaining the role of rock failure in engineering projects plus a summary of the theories governing rock failure and an explanation of the computer simulation method. It subsquently deals in detail with explaining, simulating and illustrating rock failure in laboratory and field. The concluding chapter discusses coupled modelling and the anticipated future directions for this type of computer simulation. An appendix describing the RFPA numerical model (Rock Failure Process Analysis program) is also included. About the Authors Chun'an Tang has a PhD in Mining Engineering and is a Professor at the School of Civil & Hydraulic Engineering at Dalian University of Technology in China. He is an advisor for design and stablity problem modelling in mining and civil rock engineeringand and Chairman of the China National Group of the International Society for Rock Mechanics. John Hudson is emeritus professor at Imperial College, London and is active as an independant consultant for Rock Engineering Consultants. He has a PhD in Rock Mechanics and completed over a 130 rock engineering consulting assignments in mining and civil engineering. He is a fellow at the Royal Academy of Engineering in the UK and President of the International Society for Rock Mechanics.
Author: Wei Wu
Publisher: Springer
ISBN: 3319971123
Category : Science
Languages : en
Pages : 896
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Book Description
This book compiles the first part of contributions to the China–Europe Conference on Geotechnical Engineering held 13.-16. August 2016 in Vienna, Austria. About 400 papers from 35 countries cover virtually all areas of geotechnical engineering and make this conference a truly international event. The contributions are grouped into thirteen special sessions and provide an overview of the geoengineering research and practice in China, Europe and the world: · Constitutive model · Micro-macro relationship · Numerical simulation · Laboratory testing · Geotechnical monitoring, instrumentation and field test · Foundation engineering · Underground construction · Environmental geotechnics · New geomaterials and ground improvement · Cold regions geotechnical engineering · Geohazards – risk assessment, mitigation and prevention · Unsaturated soils and energy geotechnics · Geotechnics in transportation, structural and hydraulic Engineering
Author: Wei Yao
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Rocks and rock-like materials may be failed due to high temperatures and inevitable dynamic loading. The understanding of damage and failure of rocks and rock-like materials subjected to thermal and dynamic loadings is thus important in many engineering applications. In this dissertation, the failure parameters (uniaxial compressive strength (UCS), tensile strength and fracture toughness), the failure criterion and the damage evolution of rocks and rock-like materials are investigated over a wide range of loading rates at different heat-treatment temperatures. The influence of thermally induced damage on the dynamic failure parameters of rock-like materials is investigated. The specimens heat-treated at different temperatures were tested using the split Hopkinson pressure bar (SHPB) apparatus. X-ray micro-CT scanning is used to quantify the thermally induced damage of specimens before mechanical loading. The results show that the dynamic failure parameters change with the loading rate and the heat-treatment temperature. The formulas for describing the dependence of the dynamic failure parameters on the thermal effect and the loading rate effect are established using the damage variable. To study the applicability of the dynamic failure criterion, the dynamic punch shear strength and failure parameters of rocks are systematically measured using the SHPB system. A recently developed dynamic Mohr-Coulomb theory is used to interpret the data. The applicability of the dynamic Mohr-Coulomb theory is validated, and the dynamic UCS and the dynamic tensile strength predicted with the dynamic punch shear strength through the dynamic Mohr-Coulomb theory are consistent with those directly measured. The dynamic damage evolution of rocks is studied by using the strain control technique in a modified SHPB system. The stress-strain relations of rocks with the different strain levels are obtained under different compressive loading rates. The recovered specimens, after being subjected to controlled strains, are examined using X-ray micro-CT scanning machine. Three dimensional microcrack networks induced by the different dynamic loading rates are observed and the damage evolution at different loading rates is analyzed.
