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Anh Minh Tang - One of the best experts on this subject based on the ideXlab platform.
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Analysing the form of the confined uniaxial Compression Curve of various soils
Geoderma, 2020Co-Authors: Anh Minh Tang, Javad Eslami, Pauline DefossezAbstract:International audienceThe soil compaction by vehicles is a major factor responsible for physical degradation of cultivated soils. Uniaxial confined Compression tests are usually performed to characterise the compaction properties of soil. Two main forms of Compression Curve have been observed: (i) the bi-linear Curve having an elastic rebound Curve at low stresses and a linear virgin Compression Curve at higher stresses; (ii) the S-shaped Curve having deviation of the virgin Compression Curve at high stresses. In the present work, uniaxial confined Compression tests were performed on four soils having various textures and different plasticity. Tests were performed on undisturbed and remould samples, at various initial dry bulk densities and water contents. The S-shaped Compression Curves were observed more frequently when the clay content and/or the initial water content were high. In addition, the S-shaped Curves were observed more frequently on remould soils than on undisturbed soils. The difference between the Compression of air-filled pores and that of meso-pores storing water subjected to high capillary forces could explain the observed S-shaped Curves
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Macro-microscopic one-dimensional Compression of wet granular soils by experimental investigation
E3S Web of Conferences, 2016Co-Authors: Vinh-du Than, Jean-michel Pereira, Jean Noël Roux, Patrick Aimedieu, Michel Bornert, Anh Minh TangAbstract:The presence of liquid menisci between soil particles in wet granular soils plays a key role in the macroscopic behavior. This liquid bridge between particles may also allow the existence of metastable microstructures that lead to mechanical instabilities when the soil in subjected to external loadings. In this work, the authors present an investigation into macroscopic and microscopic behaviors of wet granular soils in very loose state under one-dimensional (1D) Compression by using oedometer test combined with the X-ray computed tomography (X-ray CT) observations. The specimen is prepared in the presence of a small amount of a water meniscus by using the controlled pluviation method. The influences of various mechanical parameters are first studied on the Compression Curve. The microstructure along those Compression Curves are then analyzed by using X-ray CT to observe the arrangement of microstructure under growing of applied force.
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Macro-microscopic one-dimensional Compression of wet granular soils by experimental investigation
The 3rd European Conference on Unsaturated Soils, 2016Co-Authors: Vinh-du Than, Jean-michel Pereira, Jean Noël Roux, Patrick Aimedieu, Michel Bornert, Anh Minh TangAbstract:© 2016 The Authors. The presence of liquid menisci between soil particles in wet granular soils plays a key role in the macroscopic behavior. This liquid bridge between particles may also allow the existence of metastable microstructures that lead to mechanical instabilities when the soil in subjected to external loadings. In this work, the authors present an investigation into macroscopic and microscopic behaviors of wet granular soils in very loose state under one-dimensional (1D) Compression by using oedometer test combined with the X-ray computed tomography (X-ray CT) observations. The specimen is prepared in the presence of a small amount of a water meniscus by using the controlled pluviation method. The influences of various mechanical parameters are first studied on the Compression Curve. The microstructure along those Compression Curves are then analyzed by using X-ray CT to observe the arrangement of microstructure under growing of applied force.
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an insight into the unloading reloading loops on the Compression Curve of natural stiff clays
Applied Clay Science, 2013Co-Authors: Xuanphu Nguyen, Anh Minh Tang, Xiangling LiAbstract:Abstract Oedometer tests were carried out with loading/unloading/reloading on natural stiff clays, Ypresian clays (YPClay), taken from several depths. Common unloading/reloading loops were identified. Further examination of the unloading or reloading Curves shows that each path can be satisfactorily considered as bi-linear with a small and a larger slope separated by a threshold vertical stress. This threshold stress can be considered as the swelling pressure corresponding to the void ratio just before the unloading or reloading. Indeed, upon unloading, when the applied stress is higher than the threshold stress or swelling pressure, the mechanical effect is dominant and only small mechanical rebound is observed, corresponding to a small microstructure change; by contrast, when the applied stress is lower than the swelling pressure, physico-chemical effect becomes prevailing and soil swelling occurs with a larger microstructure change. Upon reloading, when the applied stress is lower than the swelling pressure, the microstructure is not significantly affected thanks to the contribution of the physico-chemical repulsive force, leading to a small volume change; on the contrary, beyond the swelling pressure, the mechanical effect becomes dominant giving rise to larger volume changes corresponding to the microstructure collapse. Like unsaturated expansive soils, it is found that there is a good relationship between the swelling pressure (threshold stress) and the void ratio just before the unloading or reloading. This is confirmed by the results from the data reported in the literature about other stiff clays such as Boom and London clays. It can be then deduced that the unloading/reloading loop is rather due to the competition between the mechanical and physico-chemical effects on the microstructure changes than the viscosity effect as commonly admitted.
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An insight into the unloading/reloading loops on the Compression Curve of natural stiff clays
Applied Clay Science, 2013Co-Authors: X.p. Nguyen, Anh Minh Tang, Xiangling LiAbstract:Abstract Oedometer tests were carried out with loading/unloading/reloading on natural stiff clays, Ypresian clays (YPClay), taken from several depths. Common unloading/reloading loops were identified. Further examination of the unloading or reloading Curves shows that each path can be satisfactorily considered as bi-linear with a small and a larger slope separated by a threshold vertical stress. This threshold stress can be considered as the swelling pressure corresponding to the void ratio just before the unloading or reloading. Indeed, upon unloading, when the applied stress is higher than the threshold stress or swelling pressure, the mechanical effect is dominant and only small mechanical rebound is observed, corresponding to a small microstructure change; by contrast, when the applied stress is lower than the swelling pressure, physico-chemical effect becomes prevailing and soil swelling occurs with a larger microstructure change. Upon reloading, when the applied stress is lower than the swelling pressure, the microstructure is not significantly affected thanks to the contribution of the physico-chemical repulsive force, leading to a small volume change; on the contrary, beyond the swelling pressure, the mechanical effect becomes dominant giving rise to larger volume changes corresponding to the microstructure collapse. Like unsaturated expansive soils, it is found that there is a good relationship between the swelling pressure (threshold stress) and the void ratio just before the unloading or reloading. This is confirmed by the results from the data reported in the literature about other stiff clays such as Boom and London clays. It can be then deduced that the unloading/reloading loop is rather due to the competition between the mechanical and physico-chemical effects on the microstructure changes than the viscosity effect as commonly admitted.
Tsutomu Mashimo - One of the best experts on this subject based on the ideXlab platform.
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Effect of shear strength on Hugoniot-Compression Curve and the equation of state of tungsten (W)
Journal of Applied Physics, 2016Co-Authors: Tsutomu Mashimo, Masao Kodama, E Zaretsky, Masahide Katayama, Kunihiko NagayamaAbstract:The Hugoniot data for highly dense polycrystalline tungsten were obtained for pressures above 200 GPa, and the equation of state (EOS) was determined taking into account shear strength effects. For this study, we have made some improvements in measurement system and analyses of the shock wave data. Symmetric-impact Hugoniot measurements were performed using the high-time resolution streak camera system equipped on a one-stage powder gun and two-stage light gas gun, where the effects of tilting and bowing of flyer plate on the Hugoniot data were carefully considered. The shock velocity–particle velocity (US–UP) Hugoniot relation in the plastic regime was determined to be US = 4.137 + 1.242UP km/s (UP
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effect of shear strength on hugoniot Compression Curve and the equation of state of tungsten w
Journal of Applied Physics, 2016Co-Authors: Tsutomu Mashimo, Masao Kodama, E Zaretsky, Masahide Katayama, Kunihiko NagayamaAbstract:The Hugoniot data for highly dense polycrystalline tungsten were obtained for pressures above 200 GPa, and the equation of state (EOS) was determined taking into account shear strength effects. For this study, we have made some improvements in measurement system and analyses of the shock wave data. Symmetric-impact Hugoniot measurements were performed using the high-time resolution streak camera system equipped on a one-stage powder gun and two-stage light gas gun, where the effects of tilting and bowing of flyer plate on the Hugoniot data were carefully considered. The shock velocity–particle velocity (US–UP) Hugoniot relation in the plastic regime was determined to be US = 4.137 + 1.242UP km/s (UP < 2 km/s). Ultrasonic and Velocity Interferometer System for Any Reflector measurements were also performed in this study. The zero-intercept value of the US–UP Hugoniot relation was found to be slightly larger than the ultrasonic bulk sound velocity (4.023 km/s). The hypothetical hydrostatic isothermal Us–Up ...
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hugoniot Compression Curve of zr based bulk metallic glass
Applied Physics Letters, 2006Co-Authors: Tsutomu Mashimo, Hiroaki Togo, Yuyang Zhang, Y Uemura, T Kinoshita, M Kodama, Yoshihito KawamuraAbstract:The Hugoniot-Compression Curves of the Zr-based bulk metallic glass (Zr55Al10Ni5Cu30 in at. %) and the metallic compound crystal with the same composition were measured by means of the inclined-mirror photographic technique. A kink was observed on the Hugoniot Curve at 14GPa for the glass probably due to phase transition, while no kink was observed for the crystal. The Hugoniot elastic limit stress (6.2GPa) of the glass was comparable to one of the crystal.
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Equation of state of NiO studied by shock Compression
Journal of Physics and Chemistry of Solids, 1999Co-Authors: Yuichi Noguchi, Tsutomu Mashimo, Masakazu Uchino, Hideaki Hikosaka, Toshiyuki Atou, Keiji Kusaba, Kiyoto Fukuoka, Y. SyonoAbstract:Abstract Shock Compression experiments on NiO single crystals, grown by the Verneuil method, have been carried out up to 147 GPa using both propellant and two-stage light-gas guns. The shock states, observed by streak photography, were analyzed by the free-surface approximation and impedance match solution. The determined pressure–volume relation showed no discontinuous volume decrease, indicating that NiO remains with the NaCl-type structure up to 147 GPa. The shock Compression Curve yields the isothermal Compression Curve described by a bulk modulus K =191 GPa and its pressure derivative K ′=3.9 ( K ″=−0.03 GPa −1 ).
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Measurements of the Hugoniot-Compression Curve of a LiF single crystal by the inclined-mirror method
22nd International Congress on High-Speed Photography and Photonics, 1997Co-Authors: Tsutomu Mashimo, Masahide Kaetsu, Mazakazu UchinoAbstract:The shock Compression behavior of LiF has not been well studied in the pressure region between several and several 10s of GPa. In this study, the Hugoniot-measurements experiments were performed on a LiF single crystal for the and axis orientations in such pressure region by means of the inclined-mirror method combined with a powder gas. As a result, anisotropic Hugoniot-Compression behaviors were observed. The shock front profiles showed an anomalous multi-wave structure, which were consistent with the VISAR measurements. The final Hugoniot points along the axis roughly coincided with the static Compression Curve, but, those along the axis were situated in the higher stress region than those of the axis and converged to them at up to 15 GPa. The Hugoniot data in the higher pressure region coincide with those obtained by the flash-gap method.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Kunihiko Nagayama - One of the best experts on this subject based on the ideXlab platform.
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Effect of shear strength on Hugoniot-Compression Curve and the equation of state of tungsten (W)
Journal of Applied Physics, 2016Co-Authors: Tsutomu Mashimo, Masao Kodama, E Zaretsky, Masahide Katayama, Kunihiko NagayamaAbstract:The Hugoniot data for highly dense polycrystalline tungsten were obtained for pressures above 200 GPa, and the equation of state (EOS) was determined taking into account shear strength effects. For this study, we have made some improvements in measurement system and analyses of the shock wave data. Symmetric-impact Hugoniot measurements were performed using the high-time resolution streak camera system equipped on a one-stage powder gun and two-stage light gas gun, where the effects of tilting and bowing of flyer plate on the Hugoniot data were carefully considered. The shock velocity–particle velocity (US–UP) Hugoniot relation in the plastic regime was determined to be US = 4.137 + 1.242UP km/s (UP
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effect of shear strength on hugoniot Compression Curve and the equation of state of tungsten w
Journal of Applied Physics, 2016Co-Authors: Tsutomu Mashimo, Masao Kodama, E Zaretsky, Masahide Katayama, Kunihiko NagayamaAbstract:The Hugoniot data for highly dense polycrystalline tungsten were obtained for pressures above 200 GPa, and the equation of state (EOS) was determined taking into account shear strength effects. For this study, we have made some improvements in measurement system and analyses of the shock wave data. Symmetric-impact Hugoniot measurements were performed using the high-time resolution streak camera system equipped on a one-stage powder gun and two-stage light gas gun, where the effects of tilting and bowing of flyer plate on the Hugoniot data were carefully considered. The shock velocity–particle velocity (US–UP) Hugoniot relation in the plastic regime was determined to be US = 4.137 + 1.242UP km/s (UP < 2 km/s). Ultrasonic and Velocity Interferometer System for Any Reflector measurements were also performed in this study. The zero-intercept value of the US–UP Hugoniot relation was found to be slightly larger than the ultrasonic bulk sound velocity (4.023 km/s). The hypothetical hydrostatic isothermal Us–Up ...
Xiangling Li - One of the best experts on this subject based on the ideXlab platform.
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an insight into the unloading reloading loops on the Compression Curve of natural stiff clays
Applied Clay Science, 2013Co-Authors: Xuanphu Nguyen, Anh Minh Tang, Xiangling LiAbstract:Abstract Oedometer tests were carried out with loading/unloading/reloading on natural stiff clays, Ypresian clays (YPClay), taken from several depths. Common unloading/reloading loops were identified. Further examination of the unloading or reloading Curves shows that each path can be satisfactorily considered as bi-linear with a small and a larger slope separated by a threshold vertical stress. This threshold stress can be considered as the swelling pressure corresponding to the void ratio just before the unloading or reloading. Indeed, upon unloading, when the applied stress is higher than the threshold stress or swelling pressure, the mechanical effect is dominant and only small mechanical rebound is observed, corresponding to a small microstructure change; by contrast, when the applied stress is lower than the swelling pressure, physico-chemical effect becomes prevailing and soil swelling occurs with a larger microstructure change. Upon reloading, when the applied stress is lower than the swelling pressure, the microstructure is not significantly affected thanks to the contribution of the physico-chemical repulsive force, leading to a small volume change; on the contrary, beyond the swelling pressure, the mechanical effect becomes dominant giving rise to larger volume changes corresponding to the microstructure collapse. Like unsaturated expansive soils, it is found that there is a good relationship between the swelling pressure (threshold stress) and the void ratio just before the unloading or reloading. This is confirmed by the results from the data reported in the literature about other stiff clays such as Boom and London clays. It can be then deduced that the unloading/reloading loop is rather due to the competition between the mechanical and physico-chemical effects on the microstructure changes than the viscosity effect as commonly admitted.
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An insight into the unloading/reloading loops on the Compression Curve of natural stiff clays
Applied Clay Science, 2013Co-Authors: X.p. Nguyen, Anh Minh Tang, Xiangling LiAbstract:Abstract Oedometer tests were carried out with loading/unloading/reloading on natural stiff clays, Ypresian clays (YPClay), taken from several depths. Common unloading/reloading loops were identified. Further examination of the unloading or reloading Curves shows that each path can be satisfactorily considered as bi-linear with a small and a larger slope separated by a threshold vertical stress. This threshold stress can be considered as the swelling pressure corresponding to the void ratio just before the unloading or reloading. Indeed, upon unloading, when the applied stress is higher than the threshold stress or swelling pressure, the mechanical effect is dominant and only small mechanical rebound is observed, corresponding to a small microstructure change; by contrast, when the applied stress is lower than the swelling pressure, physico-chemical effect becomes prevailing and soil swelling occurs with a larger microstructure change. Upon reloading, when the applied stress is lower than the swelling pressure, the microstructure is not significantly affected thanks to the contribution of the physico-chemical repulsive force, leading to a small volume change; on the contrary, beyond the swelling pressure, the mechanical effect becomes dominant giving rise to larger volume changes corresponding to the microstructure collapse. Like unsaturated expansive soils, it is found that there is a good relationship between the swelling pressure (threshold stress) and the void ratio just before the unloading or reloading. This is confirmed by the results from the data reported in the literature about other stiff clays such as Boom and London clays. It can be then deduced that the unloading/reloading loop is rather due to the competition between the mechanical and physico-chemical effects on the microstructure changes than the viscosity effect as commonly admitted.
Pauline Defossez - One of the best experts on this subject based on the ideXlab platform.
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Analysing the form of the confined uniaxial Compression Curve of various soils
Geoderma, 2020Co-Authors: Anh Minh Tang, Javad Eslami, Pauline DefossezAbstract:International audienceThe soil compaction by vehicles is a major factor responsible for physical degradation of cultivated soils. Uniaxial confined Compression tests are usually performed to characterise the compaction properties of soil. Two main forms of Compression Curve have been observed: (i) the bi-linear Curve having an elastic rebound Curve at low stresses and a linear virgin Compression Curve at higher stresses; (ii) the S-shaped Curve having deviation of the virgin Compression Curve at high stresses. In the present work, uniaxial confined Compression tests were performed on four soils having various textures and different plasticity. Tests were performed on undisturbed and remould samples, at various initial dry bulk densities and water contents. The S-shaped Compression Curves were observed more frequently when the clay content and/or the initial water content were high. In addition, the S-shaped Curves were observed more frequently on remould soils than on undisturbed soils. The difference between the Compression of air-filled pores and that of meso-pores storing water subjected to high capillary forces could explain the observed S-shaped Curves
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analysing the form of the confined uniaxial Compression Curve of various soils
Geoderma, 2009Co-Authors: Anh Minh Tang, Javad Eslami, Pauline DefossezAbstract:The soil compaction by vehicles is a major factor responsible for physical degradation of cultivated soils. Uniaxial confined Compression tests are usually performed to characterise the compaction properties of soil. Two main forms of Compression Curve have been observed: (i) the bi-linear Curve having an elastic rebound Curve at low stresses and a linear virgin Compression Curve at higher stresses; (ii) the S-shaped Curve having deviation of the virgin Compression Curve at high stresses. In the present work, uniaxial confined Compression tests were performed on four soils having various textures and different plasticity. Tests were performed on undisturbed and remould samples, at various initial dry bulk densities and water contents. The S-shaped Compression Curves were observed more frequently when the clay content and/or the initial water content were high. In addition, the S-shaped Curves were observed more frequently on remould soils than on undisturbed soils. The difference between the Compression of air-filled pores and that of meso-pores storing water subjected to high capillary forces could explain the observed S-shaped Curves.