The Experts below are selected from a list of 33378 Experts worldwide ranked by ideXlab platform
Seongyeong Yang - One of the best experts on this subject based on the ideXlab platform.
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water entry pressure and Friction Angle in an artificially synthesized water repellent silty soil
Vadose Zone Journal, 2015Co-Authors: Changho Lee, Heui Jean Yang, Tae Sup Yun, Young Min Choi, Seongyeong YangAbstract:Water-repellent soils possess unique hydraulic and mechanical behaviors that confer large potential for their use in geotechnical applications because particle-scale surface-wettability characteristics significantly influence macroscale manifestations. This study examined the hydraulic and mechanical behavior of an artificially created water-repellent silty soil with four different concentrations of a reactive organo-silane solution. A series of laboratory tests was performed that included measurements of water-droplet penetration time (WDPT), water-entry pressure (WEP), flow rate, and Friction Angle. Experimental results showed that the artificial treatment produced a unique range of porosity values depending on the concentration and that the WDPT and WEP increased with decreasing porosity and increasing concentration. A gravimetric fraction of 40% water-repellent particles was sufficient for bulk soils to exhibit water repellency. The flow rate of specimens with a high concentration of reactive organo-silane tended to be high due to the resulting high degree of saturation on water permeation. In contrast, Friction Angles tended to decrease with increasing concentration of organo-silane solution under dry conditions and remained quasi-constant on wetting, regardless of the degree of saturation.
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Water‐Entry Pressure and Friction Angle in an Artificially Synthesized Water‐Repellent Silty Soil
Vadose Zone Journal, 2015Co-Authors: Changho Lee, Heui Jean Yang, Tae Sup Yun, Young Min Choi, Seongyeong YangAbstract:Water-repellent soils possess unique hydraulic and mechanical behaviors that confer large potential for their use in geotechnical applications because particle-scale surface-wettability characteristics significantly influence macroscale manifestations. This study examined the hydraulic and mechanical behavior of an artificially created water-repellent silty soil with four different concentrations of a reactive organo-silane solution. A series of laboratory tests was performed that included measurements of water-droplet penetration time (WDPT), water-entry pressure (WEP), flow rate, and Friction Angle. Experimental results showed that the artificial treatment produced a unique range of porosity values depending on the concentration and that the WDPT and WEP increased with decreasing porosity and increasing concentration. A gravimetric fraction of 40% water-repellent particles was sufficient for bulk soils to exhibit water repellency. The flow rate of specimens with a high concentration of reactive organo-silane tended to be high due to the resulting high degree of saturation on water permeation. In contrast, Friction Angles tended to decrease with increasing concentration of organo-silane solution under dry conditions and remained quasi-constant on wetting, regardless of the degree of saturation.
D. Poulain - One of the best experts on this subject based on the ideXlab platform.
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Determination of geomembrane - protective geotextile Friction Angle: an insight into the shear rate effect
Geotextiles and Geomembranes, 2020Co-Authors: G. Stoltz, S. Nicaise, G. Veylon, D. PoulainAbstract:This study investigates how the shear rate can affect the geomembrane - protective geotextile Friction Angle. Four types of geomembranes (GMB) were considered (EPDM, HPDE, PP, and PVC) and a single nonwoven needle-punched geotextile (GTXnw) was used to make the interfaces with the geomembrane. Three shear devices were used: a large-scale inclined plane (IP), a shear box (SB), and a small-scale shear device (ssSD). The ssSD allows two shear modes to be compared: one mode involves incrementally increasing the shear stress, and the other involves imposing a constant tangential velocity at the interface. Only the PP GMB- GTXnw was tested with the SB and the ssSD. Inclined plane standardised tests show that for the three interfaces that undergoes gradual sliding (EPDM, PP and PVC GMB- GTXnw), it is shown that a step-by-step experimental procedure gives significantly lower interface Friction Angle than that given by the procedure from the current international standard, which is explained by the increase of interface shear stress with sliding speed. These observations are confirmed by shear box tests. One major practical result is that, following the nature of geosynthetics, the shear rate applied in large-scale shear box tests should be adapted to assess a safety value of a geosynthetic - geosynthetic interface Friction Angle.
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Determination of geomembrane – protective geotextile Friction Angle: An insight into the shear rate effect
Geotextiles and Geomembranes, 2020Co-Authors: G. Stoltz, S. Nicaise, G. Veylon, D. PoulainAbstract:Abstract This study investigates how the shear rate can affect the geomembrane – protective geotextile Friction Angle. Four types of geomembranes (GMB) were considered (EPDM, HPDE, PP, and PVC) and a single nonwoven needle-punched geotextile (GTXnw) was used to make the interfaces with the geomembrane. Three shear devices were used: a large-scale inclined plane (IP), a shear box (SB), and a small-scale shear device (ssSD). The ssSD allows two shear modes to be compared: one mode involves incrementally increasing the shear stress, and the other involves imposing a constant tangential velocity at the interface. Only the PP GMB- GTXnw was tested with the SB and the ssSD. Inclined plane standardised tests show that for the three interfaces that undergoes gradual sliding (EPDM, PP and PVC GMB- GTXnw), it is shown that a step-by-step experimental procedure gives significantly lower interface Friction Angle than that given by the procedure from the current international standard, which is explained by the increase of interface shear stress with sliding speed. These observations are confirmed by shear box tests. One major practical result is that, following the nature of geosynthetics, the shear rate applied in large-scale shear box tests should be adapted to assess a safety value of a geosynthetic - geosynthetic interface Friction Angle.
B. Indraratna - One of the best experts on this subject based on the ideXlab platform.
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The effect of normal stress-Friction Angle relationship on the stability analysis of a rockfill dam
Geotechnical & Geological Engineering, 1994Co-Authors: B. IndraratnaAbstract:Accurate stability analysis must consider the variation of the Angle of Friction of rockfill with the confining pressure. In reality, with increasing depth of a rockfill dam, the apparent Friction Angle decreases, whereas near the surface it tends to be higher. Conventional methods which employ a constant Friction Angle throughout the depth of a rockfill shell often yield a lower factor of safety (conservative) for shallow slip planes. On the contrary, they produce a higher factor of safety for deepseated slips subjected to increased normal (confining) stresses. This paper compares the constant Friction Angle approach with the variable Friction Angle method based on the stability analysis of a large rockfill dam, and the associated practical implications are discussed. In the latter analysis, the effect of normal stress on the Friction Angle of rockfill is incorporated through experimental observations.
Dhani B Narejo - One of the best experts on this subject based on the ideXlab platform.
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a simple tilt table device to measure index Friction Angle of geosynthetics
Geotextiles and Geomembranes, 2003Co-Authors: Dhani B NarejoAbstract:Abstract Interface shear strength is known to be influenced by surface features of planar materials. The tilt table test is one of the available methods for measuring the Friction effects of surface characteristics. This paper describes a simple tilt table device for measuring index Friction Angle of geosynthetics. Test results are presented for various types of geomembranes, geotextiles and geonets. Friction Angle is found to depend on the product surface being evaluated. The precision of the test is found to be typical of many other procedures used for quality control and conformance testing of geosynthetics.
Changho Lee - One of the best experts on this subject based on the ideXlab platform.
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water entry pressure and Friction Angle in an artificially synthesized water repellent silty soil
Vadose Zone Journal, 2015Co-Authors: Changho Lee, Heui Jean Yang, Tae Sup Yun, Young Min Choi, Seongyeong YangAbstract:Water-repellent soils possess unique hydraulic and mechanical behaviors that confer large potential for their use in geotechnical applications because particle-scale surface-wettability characteristics significantly influence macroscale manifestations. This study examined the hydraulic and mechanical behavior of an artificially created water-repellent silty soil with four different concentrations of a reactive organo-silane solution. A series of laboratory tests was performed that included measurements of water-droplet penetration time (WDPT), water-entry pressure (WEP), flow rate, and Friction Angle. Experimental results showed that the artificial treatment produced a unique range of porosity values depending on the concentration and that the WDPT and WEP increased with decreasing porosity and increasing concentration. A gravimetric fraction of 40% water-repellent particles was sufficient for bulk soils to exhibit water repellency. The flow rate of specimens with a high concentration of reactive organo-silane tended to be high due to the resulting high degree of saturation on water permeation. In contrast, Friction Angles tended to decrease with increasing concentration of organo-silane solution under dry conditions and remained quasi-constant on wetting, regardless of the degree of saturation.
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Water‐Entry Pressure and Friction Angle in an Artificially Synthesized Water‐Repellent Silty Soil
Vadose Zone Journal, 2015Co-Authors: Changho Lee, Heui Jean Yang, Tae Sup Yun, Young Min Choi, Seongyeong YangAbstract:Water-repellent soils possess unique hydraulic and mechanical behaviors that confer large potential for their use in geotechnical applications because particle-scale surface-wettability characteristics significantly influence macroscale manifestations. This study examined the hydraulic and mechanical behavior of an artificially created water-repellent silty soil with four different concentrations of a reactive organo-silane solution. A series of laboratory tests was performed that included measurements of water-droplet penetration time (WDPT), water-entry pressure (WEP), flow rate, and Friction Angle. Experimental results showed that the artificial treatment produced a unique range of porosity values depending on the concentration and that the WDPT and WEP increased with decreasing porosity and increasing concentration. A gravimetric fraction of 40% water-repellent particles was sufficient for bulk soils to exhibit water repellency. The flow rate of specimens with a high concentration of reactive organo-silane tended to be high due to the resulting high degree of saturation on water permeation. In contrast, Friction Angles tended to decrease with increasing concentration of organo-silane solution under dry conditions and remained quasi-constant on wetting, regardless of the degree of saturation.
