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Jonny Rutqvist - One of the best experts on this subject based on the ideXlab platform.
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Extension of TOUGH-FLAC to the finite strain framework
Computers & Geosciences, 2017Co-Authors: Laura Blanco-martín, Jonny Rutqvist, Jt BirkholzerAbstract:Abstract The TOUGH-FLAC simulator for coupled thermal-hydraulic-mechanical processes modeling has been extended to the finite strain framework. In the approach selected, this extension has required modifications to the flow simulator (TOUGH2) and to the coupling scheme between the geomechanics and the flow sub-problems. In TOUGH2, the mass and energy balance equations have been extended to account for volume changes. Additionally, as large deformations are computed by FLAC3D, the geometry is updated in the flow sub-problem. The Voronoi partition needed in TOUGH2 is computed using an external open source library (Voro++) that uses the centroids of the deformed geomechanics mesh as generators of the Voronoi diagram. TOUGH-FLAC in infinitesimal and finite strain frameworks is verified against analytical solutions and other approaches to couple flow and geomechanics. Within the finite strain framework, TOUGH-FLAC is also successfully applied to a large-scale case. The extension of TOUGH-FLAC to the finite strain framework has little impact to the user as only one additional executable is needed (for Voro++), and the input files and the workflow of a simulation are the same as in standard TOUGH-FLAC. With this new provision for finite strains, TOUGH-FLAC can be used in the analysis of a wider range of engineering problems, and the areas of application of this simulator are therefore broadened.
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Status of the TOUGH-FLAC simulator and recent applications related to coupled fluid flow and crustal deformations
Computers & Geosciences, 2011Co-Authors: Jonny RutqvistAbstract:This paper presents recent advancement in and applications of TOUGH-FLAC, a simulator for multiphase fluid flow and geomechanics. The TOUGH-FLAC simulator links the TOUGH family multiphase fluid and heat transport codes with the commercial FLAC^3^D geomechanical simulator. The most significant new TOUGH-FLAC development in the past few years is a revised architecture, enabling a more rigorous and tight coupling procedure with improved computational efficiency. The applications presented in this paper are related to modeling of crustal deformations caused by deep underground fluid movements and pressure changes as a result of both industrial activities (the In Salah CO"2 Storage Project and the Geysers Geothermal Field) and natural events (the 1960s Matsushiro Earthquake Swarm). Finally, the paper provides some perspectives on the future of TOUGH-FLAC in light of its applicability to practical problems and the need for high-performance computing capabilities for field-scale problems, such as industrial-scale CO"2 storage and enhanced geothermal systems. It is concluded that despite some limitations to fully adapting a commercial code such as FLAC^3^D for some specialized research and computational needs, TOUGH-FLAC is likely to remain a pragmatic simulation approach, with an increasing number of users in both academia and industry.
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Implementation of the Barcelona Basic Model into TOUGH-FLAC for simulations of the geomechanical behavior of unsaturated soils
Computers & Geosciences, 2011Co-Authors: Jonny Rutqvist, Yuji Ijiri, Hajime YamamotoAbstract:This paper presents the implementation of the Barcelona Basic Model (BBM) into the TOUGH-FLAC simulator analyzing the geomechanical behavior of unsaturated soils. We implemented the BBM into TOUGH-FLAC by (1) extending an existing FLAC^3^D module for the Modified Cam-Clay (MCC) model in FLAC^3^D and (2) adding computational routines for suction-dependent strain and net stress (i.e., total stress minus gas pressure) for unsaturated soils. We implemented a thermo-elasto-plastic version of the BBM, wherein the soil strength depends on both suction and temperature. The implementation of the BBM into TOUGH-FLAC was verified and tested against several published numerical model simulations and laboratory experiments involving the coupled thermal-hydrological-mechanical (THM) behavior of unsaturated soils. The simulation tests included modeling the mechanical behavior of bentonite-sand mixtures, which are being considered as back-fill and buffer materials for geological disposal of spent nuclear fuel. We also tested and demonstrated the use of the BBM and TOUGH-FLAC for a problem involving the coupled THM processes within a bentonite-backfilled nuclear waste emplacement tunnel. The simulation results indicated complex geomechanical behavior of the bentonite backfill, including a nonuniform distribution of buffer porosity and density that could not be captured in an alternative, simplified, linear-elastic swelling model. As a result of the work presented in this paper, TOUGH-FLAC with BBM is now fully operational and ready to be applied to problems associated with nuclear waste disposal in bentonite-backfilled tunnels, as well as other scientific and engineering problems related to the mechanical behavior of unsaturated soils.
M. Cai - One of the best experts on this subject based on the ideXlab platform.
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FLAC specfem2d coupled numerical simulation of wavefields near excavation boundaries in underground mines
Computers & Geosciences, 2016Co-Authors: Xin Wang, M. CaiAbstract:A nonlinear velocity model that considers the influence of confinement and rock mass failure on wave velocity is developed. A numerical method, which couples FLAC and SPECFEM2D, is developed for ground motion modeling near excavation boundaries in underground mines. The motivation of developing the FLAC/SPECFEM2D coupled approach is to take merits of each code, such as the stress analysis capability in FLAC and the powerful wave propagation analysis capability in SPECFEM2D. Because stress redistribution and failure of the rock mass around an excavation are considered, realistic non-uniform velocity fields for the SPECFEM2D model can be obtained, and this is a notable feature of this study. Very large differences in wavefields and ground motion are observed between the results from the non-uniform and the uniform velocity models. If the non-uniform velocity model is used, the ground motion around a stope can be amplified up to five times larger than that given by the design scaling law. If a uniform velocity model is used, the amplification factor is only about three. Using the FLAC/SPECFEM2D coupled modeling approach, accurate velocity models can be constructed and this in turn will assist in predicting ground motions accurately around underground excavations. Display Omitted A nonlinear velocity model is proposed for wave field simulation.A FLAC/SPECFEM2D coupled wave propagation simulation approach is proposed.Show that stress redistribution and rock mass failure affect seismic wave patterns.Large site amplification occurs in low confined zones and on excavation surfaces.
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FLAC/SPECFEM2D coupled numerical simulation of wavefields near excavation boundaries in underground mines
Computers & Geosciences, 2016Co-Authors: Xin Wang, M. CaiAbstract:A nonlinear velocity model that considers the influence of confinement and rock mass failure on wave velocity is developed. A numerical method, which couples FLAC and SPECFEM2D, is developed for ground motion modeling near excavation boundaries in underground mines. The motivation of developing the FLAC/SPECFEM2D coupled approach is to take merits of each code, such as the stress analysis capability in FLAC and the powerful wave propagation analysis capability in SPECFEM2D. Because stress redistribution and failure of the rock mass around an excavation are considered, realistic non-uniform velocity fields for the SPECFEM2D model can be obtained, and this is a notable feature of this study. Very large differences in wavefields and ground motion are observed between the results from the non-uniform and the uniform velocity models. If the non-uniform velocity model is used, the ground motion around a stope can be amplified up to five times larger than that given by the design scaling law. If a uniform velocity model is used, the amplification factor is only about three. Using the FLAC/SPECFEM2D coupled modeling approach, accurate velocity models can be constructed and this in turn will assist in predicting ground motions accurately around underground excavations. Display Omitted A nonlinear velocity model is proposed for wave field simulation.A FLAC/SPECFEM2D coupled wave propagation simulation approach is proposed.Show that stress redistribution and rock mass failure affect seismic wave patterns.Large site amplification occurs in low confined zones and on excavation surfaces.
Jichang Jian - One of the best experts on this subject based on the ideXlab platform.
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Immunogenic and protective effects of a DNA vaccine containing flagellin FLAC gene against Vibrio alginolyticus in red snapper(Lutjanus sanguineus)
Journal of Fisheries of China, 2013Co-Authors: Haiying Liang, Yongxin Cheng, Jichang JianAbstract:In order to study the immunogenic and protective effects of DNA vaccine,plasmid DNA encoding flagellin FLAC gene(designated as pcDNA-FLAC)was used as a DNA vaccine to immunize red snapper(Lutjanus sanguineus).The distribution,expression and immunoprotection of the DNA vaccine were analyzed in tissues of the red snapper by PCR,RT-PCR and challenge test.PCR results indicated that pcDNA-FLAC was distributed in liver,spleen,kidney,gill and injection site muscle at 7-28 days after vaccination.RT-PCR results indicated that the FLAC gene was expressed in all above tissues of vaccinated fish at 7-28 days after vaccination.These results demonstrated that the DNA vaccine was distributed and FLAC gene was expressed in various tissues of vaccinated fish.Red snapper immunized with DNA vaccine showed higher serum antibody levels at 7-28 days after vaccination,compared to fish vaccinated with the control eukaryotic expression vector pcDNA3.1 and PBS.In addition,fish immunized with DNA vaccine developed a protective response to live V.alginolyticus challenge 28 days post-inoculation,as demonstrated by increased survival of vaccinated fish over the control fish.This study indicates that pcDNA-FLAC is an effective vaccine candidate against V.alginolyticus infection.
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Expression, characterization and immunogenicity of flagellin FLAC from Vibrio alginolyticus strain HY9901.
Fish & shellfish immunology, 2010Co-Authors: Haiying Liang, Xia Liqun, Jichang JianAbstract:Vibrio alginolyticus is one of ubiquitous pathogens infecting human and marine animals. Flagellins of bacteria play an important role in infecting animals and inducing host immune response. In the present research, flagellin FLAC gene of V. alginolyticus strain HY9901 was cloned and expressed. The open reading frame of FLAC gene contains 1155 bp and the putative protein consists of 384 amino acid residues. Polyclonal antibodies were raised in mouse against the purified recombinant FLAC protein and the reaction of the antibody was confirmed by western blot analysis using the FLAC protein and crude protein extracts of V. alginolyticus. Red snapper (Lutjanus sanguineus) vaccinated with recombinant FLAC produced specific antibodies, and were highly resistant to infection by virulent V. alginolyticus. This study indicates that the conserved FLAC is an effective vaccine candidate against V. alginolyticus infection.
Jt Birkholzer - One of the best experts on this subject based on the ideXlab platform.
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Extension of TOUGH-FLAC to the finite strain framework
eScholarship University of California, 2017Co-Authors: Blanco-martín L, Rutqvist J, Jt BirkholzerAbstract:© 2016 Elsevier Ltd The TOUGH-FLAC simulator for coupled thermal-hydraulic-mechanical processes modeling has been extended to the finite strain framework. In the approach selected, this extension has required modifications to the flow simulator (TOUGH2) and to the coupling scheme between the geomechanics and the flow sub-problems. In TOUGH2, the mass and energy balance equations have been extended to account for volume changes. Additionally, as large deformations are computed by FLAC3D, the geometry is updated in the flow sub-problem. The Voronoi partition needed in TOUGH2 is computed using an external open source library (Voro++) that uses the centroids of the deformed geomechanics mesh as generators of the Voronoi diagram. TOUGH-FLAC in infinitesimal and finite strain frameworks is verified against analytical solutions and other approaches to couple flow and geomechanics. Within the finite strain framework, TOUGH-FLAC is also successfully applied to a large-scale case. The extension of TOUGH-FLAC to the finite strain framework has little impact to the user as only one additional executable is needed (for Voro++), and the input files and the workflow of a simulation are the same as in standard TOUGH-FLAC. With this new provision for finite strains, TOUGH-FLAC can be used in the analysis of a wider range of engineering problems, and the areas of application of this simulator are therefore broadened
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Extension of TOUGH-FLAC to the finite strain framework
Computers & Geosciences, 2017Co-Authors: Laura Blanco-martín, Jonny Rutqvist, Jt BirkholzerAbstract:Abstract The TOUGH-FLAC simulator for coupled thermal-hydraulic-mechanical processes modeling has been extended to the finite strain framework. In the approach selected, this extension has required modifications to the flow simulator (TOUGH2) and to the coupling scheme between the geomechanics and the flow sub-problems. In TOUGH2, the mass and energy balance equations have been extended to account for volume changes. Additionally, as large deformations are computed by FLAC3D, the geometry is updated in the flow sub-problem. The Voronoi partition needed in TOUGH2 is computed using an external open source library (Voro++) that uses the centroids of the deformed geomechanics mesh as generators of the Voronoi diagram. TOUGH-FLAC in infinitesimal and finite strain frameworks is verified against analytical solutions and other approaches to couple flow and geomechanics. Within the finite strain framework, TOUGH-FLAC is also successfully applied to a large-scale case. The extension of TOUGH-FLAC to the finite strain framework has little impact to the user as only one additional executable is needed (for Voro++), and the input files and the workflow of a simulation are the same as in standard TOUGH-FLAC. With this new provision for finite strains, TOUGH-FLAC can be used in the analysis of a wider range of engineering problems, and the areas of application of this simulator are therefore broadened.
Xin Wang - One of the best experts on this subject based on the ideXlab platform.
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FLAC specfem2d coupled numerical simulation of wavefields near excavation boundaries in underground mines
Computers & Geosciences, 2016Co-Authors: Xin Wang, M. CaiAbstract:A nonlinear velocity model that considers the influence of confinement and rock mass failure on wave velocity is developed. A numerical method, which couples FLAC and SPECFEM2D, is developed for ground motion modeling near excavation boundaries in underground mines. The motivation of developing the FLAC/SPECFEM2D coupled approach is to take merits of each code, such as the stress analysis capability in FLAC and the powerful wave propagation analysis capability in SPECFEM2D. Because stress redistribution and failure of the rock mass around an excavation are considered, realistic non-uniform velocity fields for the SPECFEM2D model can be obtained, and this is a notable feature of this study. Very large differences in wavefields and ground motion are observed between the results from the non-uniform and the uniform velocity models. If the non-uniform velocity model is used, the ground motion around a stope can be amplified up to five times larger than that given by the design scaling law. If a uniform velocity model is used, the amplification factor is only about three. Using the FLAC/SPECFEM2D coupled modeling approach, accurate velocity models can be constructed and this in turn will assist in predicting ground motions accurately around underground excavations. Display Omitted A nonlinear velocity model is proposed for wave field simulation.A FLAC/SPECFEM2D coupled wave propagation simulation approach is proposed.Show that stress redistribution and rock mass failure affect seismic wave patterns.Large site amplification occurs in low confined zones and on excavation surfaces.
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FLAC/SPECFEM2D coupled numerical simulation of wavefields near excavation boundaries in underground mines
Computers & Geosciences, 2016Co-Authors: Xin Wang, M. CaiAbstract:A nonlinear velocity model that considers the influence of confinement and rock mass failure on wave velocity is developed. A numerical method, which couples FLAC and SPECFEM2D, is developed for ground motion modeling near excavation boundaries in underground mines. The motivation of developing the FLAC/SPECFEM2D coupled approach is to take merits of each code, such as the stress analysis capability in FLAC and the powerful wave propagation analysis capability in SPECFEM2D. Because stress redistribution and failure of the rock mass around an excavation are considered, realistic non-uniform velocity fields for the SPECFEM2D model can be obtained, and this is a notable feature of this study. Very large differences in wavefields and ground motion are observed between the results from the non-uniform and the uniform velocity models. If the non-uniform velocity model is used, the ground motion around a stope can be amplified up to five times larger than that given by the design scaling law. If a uniform velocity model is used, the amplification factor is only about three. Using the FLAC/SPECFEM2D coupled modeling approach, accurate velocity models can be constructed and this in turn will assist in predicting ground motions accurately around underground excavations. Display Omitted A nonlinear velocity model is proposed for wave field simulation.A FLAC/SPECFEM2D coupled wave propagation simulation approach is proposed.Show that stress redistribution and rock mass failure affect seismic wave patterns.Large site amplification occurs in low confined zones and on excavation surfaces.