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Farimah Masrouri - One of the best experts on this subject based on the ideXlab platform.
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Soil Fabric of Compacted and Natural Swelling Soils Studied by Mercury Intrusion Porosimetry
Unsaturated Soils: Research and Applications, 2012Co-Authors: Hossein Nowamooz, Farimah MasrouriAbstract:This article compares the Pore Size Distribution (PSD) study of two different fine graded swelling Soils, in natural state, and remoulded at the same initial state. The Soil Fabric of these clayey Soils including the macropores, mesopores, and micropores was mainly studied by the mercury intrusion porosimetry (MIP) technique. For both Soils, the results showed clearly that the Soil Fabric of the remoulded samples compacted in the laboratory are significantly different from the natural ones. Therefore, as the artificial compacted samples do not correctly represent the natural Soil Fabric, hydro-mechanical parameters measured on them would be different from those obtained on the intact natural samples.
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Soil Fabric and Soil Water Retention Curve of a Compacted Silt-Bentonites
Geotechnical Testing Journal, 2012Co-Authors: Hossein Nowamooz, Farimah MasrouriAbstract:This study presents the effects of the initial dry density and the initial water content on the Soil water retention curve (SWRC) of a compacted bentonite/silt mixture during a single wetting and drying path. The samples were compacted at two different loose and dense states and at different constant initial water contents: 15% representing the dry side of the optimum, 25% representing the optimum point, and 30% representing the wet side of the optimum compacted. The initial Soil Fabric of each compacted sample was also studied by the mercury intrusion prosimetry (MIP) tests. To obtain the SWRCs, two suction imposition techniques were used: the osmotic method for matrix suctions below 8.5 MPa and the vapor equilibrium technique for suctions higher than 8.5 MPa. The MIP tests were then used to fit the SWRC of each compacted sample in the degree of saturation-suction plane. The initial Soil Fabrics play an important role on the hydric response of the samples. Generally it can be stated that a good correspondence between MIP results and the SWRCs was found on the wetting path for the low suctions close to saturation and on the drying path for the higher suctions.
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relationships between Soil Fabric and suction cycles in compacted swelling Soils
Engineering Geology, 2010Co-Authors: Hossein Nowamooz, Farimah MasrouriAbstract:Abstract This study presents the influence of suction variation on the Fabric of two clayey Soils, using the mercury intrusion porosimetry (MIP) technique on dense and loose remoulded samples. The experimental study focussed on the evolution of the compacted Soil Fabric, including the macropores, mesopores, and micropores under various hydromechanical conditions. The variation of void ratio of both samples was initially studied during a single wetting and drying cycle. The experimental results confirm the existence of a suction limit between the meso- and macropores (sm/M) as well as the Soil “shrinkage limit” suction (sSL). The suction increase between (sm/M) and (sSL) completely eliminated the macropores and produced mesostructural rearrangement. The higher suctions modified the meso- and micropores. The measured Soil water retention curves (SWRC) of these two Soils compared with the MIP calculations showed a more reasonable agreement for the dense Soil with a fewer macropores. Moreover, several wetting and drying cycles were applied to the remoulded samples. The suction cycles produced a cumulative swelling strain for the dense Soil while a shrinkage accumulation was observed for the loose samples. The wetting/drying cycles induced an equilibrium stage in which the samples behaved in an elastic way. The analysis of the Soil Fabric at this elastic equilibrium stage showed that the suction cycles created significant macrostructural modifications and reorganization of the mesopores towards smaller sizes.
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Relationships between Soil Fabric and hydraulic properties in compacted swelling Soils
Journal of Engineering Geology, 2010Co-Authors: Hossein Nowamooz, Farimah MasrouriAbstract:This study presents the influence of suction variation on the Fabric of two clayey Soils, using the mercury intrusion porosimetry (MIP) technique on dense and loose remoulded samples. The experimental study focussed on the evolution of the compacted Soil Fabric, including the macropores, mesopores, and micropores under various hydromechanical conditions. The variation of void ratio of both samples was initially studied during a single wetting and drying cycle. The experimental results confirm the existence of a suction limit between the meso- and macropores (sm/M) as well as the Soil "shrinkage limit" suction (sSL). The suction increase between (sm/M) and (sSL) completely eliminated the macropores and produced mesostructural rearrangement. The higher suctions modified the meso- and micropores. The measured Soil water retention curves (SWRC) of these two Soils compared with the MIP calculations showed a more reasonable agreement for the dense Soil with a fewer macropores. Moreover, several wetting and drying cycles were applied to the remoulded samples. The suction cycles produced a cumulative swelling strain for the dense Soil while a shrinkage accumulation was observed for the loose samples. The wetting/drying cycles induced an equilibrium stage in which the samples behaved in an elastic way. The analysis of the Soil Fabric at this elastic equilibrium stage showed that the suction cycles created significant macrostructural modifications and reorganization of the mesopores towards smaller sizes
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Suction variations and Soil Fabric of swelling compacted Soils
Journal of Rock Mechanics and Geotechnical Engineering, 2010Co-Authors: Hossein Nowamooz, Farimah MasrouriAbstract:This study addresses firstly the Soil Fabric variations of loose and dense compacted Soil samples during a single wetting/drying cycle at suctions between 0 and 287.9 MPa using mainly the mercury intrusion porosimetry (MIP) tests. Two suction techniques were employed to apply this wide suction range: the osmotic technique for suctions less than 8.5 MPa, and the vapor equilibrium or salt solution technique for suctions higher than 8.5 MPa. Secondly, the Soil water retention curves (SWRCs) were predicted by the MIP test results for both loose and dense Soil samples. A reasonable correspondence between MIP results and SWRCs was found on the wetting path at lower suctions close to saturation and on drying path at higher suctions.
Takashi Kiyota - One of the best experts on this subject based on the ideXlab platform.
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effects of specimen density and initial cyclic loading history on correlation between shear wave velocity and liquefaction resistance of toyoura sand
Soils and Foundations, 2019Co-Authors: Takashi KiyotaAbstract:Abstract Some previous studies have shown a good correlation between the shear wave velocity, Vs, and the cyclic resistance ratio, CRR. Recently, however, a Vs-based liquefaction assessment method has become an alternative and supplementary method to the conventional NSPT-based method. It is known that the CRR is influenced not only by the specimen density, but also by the Soil Fabric. Unfortunately, there are concerns that different combinations of the effects of the specimen density and the Soil Fabric may generate different relations between Vs and the CRR even if the tested specimens are of the same Soil material. In the current study, a series of Vs measurements and undrained cyclic triaxial tests is performed on Toyoura sand specimens with different Soil Fabrics for three different specimen densities. The Fabric of the specimens is varied by applying initial cyclic loading. The results of the Vs measurements indicate that the Vs of the specimen is affected by the initial cyclic loading histories, and the results of the undrained cyclic triaxial tests show that there is a good correlation between Vs and the CRR. However, the correlation varies depending on the specimen density even when the tested material is Toyoura sand only. In other words, the Soil-type specific correlation between Vs and the CRR depends on the specimen density. Therefore, the results indicate that both Vs and the specimen density are necessary parameters for an accurate assessment of the CRR.
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Using in-situ and laboratory-measured shear wave velocities to evaluate the influence of Soil Fabric on in-situ liquefaction resistance
Soil Dynamics and Earthquake Engineering, 2019Co-Authors: Takashi Kiyota, Yuta MaekawaAbstract:Abstract It has been known that the liquefaction resistance of a particular sandy Soil is influenced by not only its density, but also the Soil Fabric. Thus, it is evident that a laboratory test that utilizes an in-situ high quality sample is necessary to investigate the effects of density and Soil Fabric on the liquefaction resistance. However, the Fabric of sandy Soil samples retrieved via conventional, and inaptly named, “undisturbed” sampling techniques is prone to disturbance during sampling and the process of sample preparation in the laboratory. Therefore, the main aim of this study is to solve this problem. In order to investigate the respective effects of density and Soil Fabric on the liquefaction resistance of sandy Soil, a series of undrained cyclic triaxial tests and Vs measurements were performed, and then the results were compared to, and analysed against, previously reported results. The results indicate that, when the Soil particles show no signs of any bonding effect (cementation effect and/or plasticity), the Vs-CRR trends of the examined Soils are consistently similar regardless of Soil type, density, fines content and confining pressure. Thus, based on the experimental and analytical findings, a method is proposed to evaluate in-situ liquefaction resistance as based on the in-situ and laboratory-measured shear wave velocities.
Hossein Nowamooz - One of the best experts on this subject based on the ideXlab platform.
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Soil Fabric of Compacted and Natural Swelling Soils Studied by Mercury Intrusion Porosimetry
Unsaturated Soils: Research and Applications, 2012Co-Authors: Hossein Nowamooz, Farimah MasrouriAbstract:This article compares the Pore Size Distribution (PSD) study of two different fine graded swelling Soils, in natural state, and remoulded at the same initial state. The Soil Fabric of these clayey Soils including the macropores, mesopores, and micropores was mainly studied by the mercury intrusion porosimetry (MIP) technique. For both Soils, the results showed clearly that the Soil Fabric of the remoulded samples compacted in the laboratory are significantly different from the natural ones. Therefore, as the artificial compacted samples do not correctly represent the natural Soil Fabric, hydro-mechanical parameters measured on them would be different from those obtained on the intact natural samples.
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Soil Fabric and Soil Water Retention Curve of a Compacted Silt-Bentonites
Geotechnical Testing Journal, 2012Co-Authors: Hossein Nowamooz, Farimah MasrouriAbstract:This study presents the effects of the initial dry density and the initial water content on the Soil water retention curve (SWRC) of a compacted bentonite/silt mixture during a single wetting and drying path. The samples were compacted at two different loose and dense states and at different constant initial water contents: 15% representing the dry side of the optimum, 25% representing the optimum point, and 30% representing the wet side of the optimum compacted. The initial Soil Fabric of each compacted sample was also studied by the mercury intrusion prosimetry (MIP) tests. To obtain the SWRCs, two suction imposition techniques were used: the osmotic method for matrix suctions below 8.5 MPa and the vapor equilibrium technique for suctions higher than 8.5 MPa. The MIP tests were then used to fit the SWRC of each compacted sample in the degree of saturation-suction plane. The initial Soil Fabrics play an important role on the hydric response of the samples. Generally it can be stated that a good correspondence between MIP results and the SWRCs was found on the wetting path for the low suctions close to saturation and on the drying path for the higher suctions.
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relationships between Soil Fabric and suction cycles in compacted swelling Soils
Engineering Geology, 2010Co-Authors: Hossein Nowamooz, Farimah MasrouriAbstract:Abstract This study presents the influence of suction variation on the Fabric of two clayey Soils, using the mercury intrusion porosimetry (MIP) technique on dense and loose remoulded samples. The experimental study focussed on the evolution of the compacted Soil Fabric, including the macropores, mesopores, and micropores under various hydromechanical conditions. The variation of void ratio of both samples was initially studied during a single wetting and drying cycle. The experimental results confirm the existence of a suction limit between the meso- and macropores (sm/M) as well as the Soil “shrinkage limit” suction (sSL). The suction increase between (sm/M) and (sSL) completely eliminated the macropores and produced mesostructural rearrangement. The higher suctions modified the meso- and micropores. The measured Soil water retention curves (SWRC) of these two Soils compared with the MIP calculations showed a more reasonable agreement for the dense Soil with a fewer macropores. Moreover, several wetting and drying cycles were applied to the remoulded samples. The suction cycles produced a cumulative swelling strain for the dense Soil while a shrinkage accumulation was observed for the loose samples. The wetting/drying cycles induced an equilibrium stage in which the samples behaved in an elastic way. The analysis of the Soil Fabric at this elastic equilibrium stage showed that the suction cycles created significant macrostructural modifications and reorganization of the mesopores towards smaller sizes.
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Relationships between Soil Fabric and hydraulic properties in compacted swelling Soils
Journal of Engineering Geology, 2010Co-Authors: Hossein Nowamooz, Farimah MasrouriAbstract:This study presents the influence of suction variation on the Fabric of two clayey Soils, using the mercury intrusion porosimetry (MIP) technique on dense and loose remoulded samples. The experimental study focussed on the evolution of the compacted Soil Fabric, including the macropores, mesopores, and micropores under various hydromechanical conditions. The variation of void ratio of both samples was initially studied during a single wetting and drying cycle. The experimental results confirm the existence of a suction limit between the meso- and macropores (sm/M) as well as the Soil "shrinkage limit" suction (sSL). The suction increase between (sm/M) and (sSL) completely eliminated the macropores and produced mesostructural rearrangement. The higher suctions modified the meso- and micropores. The measured Soil water retention curves (SWRC) of these two Soils compared with the MIP calculations showed a more reasonable agreement for the dense Soil with a fewer macropores. Moreover, several wetting and drying cycles were applied to the remoulded samples. The suction cycles produced a cumulative swelling strain for the dense Soil while a shrinkage accumulation was observed for the loose samples. The wetting/drying cycles induced an equilibrium stage in which the samples behaved in an elastic way. The analysis of the Soil Fabric at this elastic equilibrium stage showed that the suction cycles created significant macrostructural modifications and reorganization of the mesopores towards smaller sizes
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Suction variations and Soil Fabric of swelling compacted Soils
Journal of Rock Mechanics and Geotechnical Engineering, 2010Co-Authors: Hossein Nowamooz, Farimah MasrouriAbstract:This study addresses firstly the Soil Fabric variations of loose and dense compacted Soil samples during a single wetting/drying cycle at suctions between 0 and 287.9 MPa using mainly the mercury intrusion porosimetry (MIP) tests. Two suction techniques were employed to apply this wide suction range: the osmotic technique for suctions less than 8.5 MPa, and the vapor equilibrium or salt solution technique for suctions higher than 8.5 MPa. Secondly, the Soil water retention curves (SWRCs) were predicted by the MIP test results for both loose and dense Soil samples. A reasonable correspondence between MIP results and SWRCs was found on the wetting path at lower suctions close to saturation and on drying path at higher suctions.
Wenqi Ding - One of the best experts on this subject based on the ideXlab platform.
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A generalized water retention model with Soil Fabric evolution
Geomechanics for Energy and the Environment, 2021Co-Authors: Yafei Qiao, Angelica Tuttolomondo, Lyesse Laloui, Wenqi DingAbstract:Abstract This paper introduces a novel Soil–water retention curve model that considers two different mechanisms of water retention – namely capillarity and adsorption – and their evolution with Soil Fabric along a generalized stress path. The model is formulated based on a new developed framework, which is justified against experimental evidence and incorporates the following developments: (i) the characteristics of the capillary and adsorption water retention curves are identified, and an ad-hoc water retention model is developed for each mechanism; (ii) the capillary and adsorption water retention curves are related to the experimentally determinable water retention curve thanks to a newly defined parameter named “contribution factor”, which changes with the evolution of the Fabric. The proposed model is an elastoplastic water retention model and it allows to describe satisfactorily the water retention capacity of different Soils. All simulation results support the statement that the adsorptive mechanism plays a crucial rule in the high suction range while capillarity is important in the low suction range. Moreover, it is shown that the developed capillary water retention curve allows to easily compute, at any state of the Soil, a suitable capillary degree of saturation; the latter, adopted within the generalized effective stress concept, makes it possible to interpret shear strength data under different saturation conditions properly.
Yafei Qiao - One of the best experts on this subject based on the ideXlab platform.
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A generalized water retention model with Soil Fabric evolution
Geomechanics for Energy and the Environment, 2021Co-Authors: Yafei Qiao, Angelica Tuttolomondo, Lyesse Laloui, Wenqi DingAbstract:Abstract This paper introduces a novel Soil–water retention curve model that considers two different mechanisms of water retention – namely capillarity and adsorption – and their evolution with Soil Fabric along a generalized stress path. The model is formulated based on a new developed framework, which is justified against experimental evidence and incorporates the following developments: (i) the characteristics of the capillary and adsorption water retention curves are identified, and an ad-hoc water retention model is developed for each mechanism; (ii) the capillary and adsorption water retention curves are related to the experimentally determinable water retention curve thanks to a newly defined parameter named “contribution factor”, which changes with the evolution of the Fabric. The proposed model is an elastoplastic water retention model and it allows to describe satisfactorily the water retention capacity of different Soils. All simulation results support the statement that the adsorptive mechanism plays a crucial rule in the high suction range while capillarity is important in the low suction range. Moreover, it is shown that the developed capillary water retention curve allows to easily compute, at any state of the Soil, a suitable capillary degree of saturation; the latter, adopted within the generalized effective stress concept, makes it possible to interpret shear strength data under different saturation conditions properly.