A Physical Model for Sloping Capillary Barriers

Suits, L David; Sheahan, TC; Tami, Denny; Rahardjo, H.; Leong, E. C.; Fredlund, D. G.

doi:10.1520/gtj11431

Cited by 46 publications

(5 citation statements)

References 13 publications

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“…Despite the wealth of research, there are still several issues that need to be resolved with respect to geosynthetic capillary barriers. Only limited laboratory studies on capillary barriers involving fine-grained soils have been performed due to the significant time requirements, especially for low infiltration rates (Stormont and Anderson 1999;Tami et al 2004;Bathurst et al 2007). There are several issues that have led to difficulties in the evaluation of field observations of soil layers underlain by geosynthetic capillary barriers.…”

Section: Introductionmentioning

confidence: 99%

Effects of infiltration and evaporation on geosynthetic capillary barrier performance

McCartney

Zornberg

2010

Can. Geotech. J.

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This study includes an experimental investigation of the transient movement of water in unsaturated soil layers underlain by a geocomposite drainage layer (GDL) during cycles of infiltration and evaporation. The distribution in volumetric water content with depth in a soil column having a height of 1350 mm underlain by a GDL was measured during transient infiltration. The capillary break effect was observed to affect the soil up to a height of 500 mm above the GDL, with an increase in volumetric water content up to 20% above that expected for the case of infiltration under a unit hydraulic gradient. Due to the long duration of this test (2000 h), a shorter 150 mm high soil column was also evaluated to investigate the soil–GDL hydraulic interaction during cycles of infiltration and evaporation. The capillary break was observed to have re-established itself after infiltration was stopped and the soil near the interface dried. The suction and volumetric water content measured in the soil at breakthrough were consistent after multiple cycles of wetting and drying. The conditions in the soil after each breakthrough event corresponded to the point on the drying-path water retention curve of the nonwoven geotextile where it transitioned from residual to saturated conditions.

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Section: Introductionmentioning

confidence: 99%

Effects of infiltration and evaporation on geosynthetic capillary barrier performance

McCartney

Zornberg

2010

Can. Geotech. J.

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“…Moreover, the CB system has been used as a final capping system after the closure of nuclear waste facilities [9]. Some researchers have also considered the application of the CB system for the maintenance of slope stability in soil structures since it can prevent rainwater infiltration into engineered slopes [10][11][12][13][14][15][16][17][18][19]. Meanwhile, many laboratory CB model tests have been performed to examine and improve the water-shielding performance of the CB system under the influence of several factors (e.g., material properties and layer thickness) [15,[20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

“…Some researchers have also considered the application of the CB system for the maintenance of slope stability in soil structures since it can prevent rainwater infiltration into engineered slopes [10][11][12][13][14][15][16][17][18][19]. Meanwhile, many laboratory CB model tests have been performed to examine and improve the water-shielding performance of the CB system under the influence of several factors (e.g., material properties and layer thickness) [15,[20][21][22][23][24]. Numerical simulations associated with the design of a physical CB model have been also carried out under diverse conditions [16,[25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Water Shielding Performance of a Capillary Barrier System through a Small-Scale Model Test

Kim

2021

Applied Sciences

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Capillary barrier (CB) systems consisting of a fine-grained soil layer placed over a coarse-grained soil layer can generally provide a water-shielding effect, increasing the slope stability of soil structures during rainfall. In order to improve the water-shielding performance of CB systems, laboratory model tests have been previously conducted under various conditions; notably, large-scale model tests are especially required. The inefficiency in increasing the production time of CB models until now explains their high cost. In this paper, we propose a laboratory small-scale CB (SSCB) model test for a quick and efficient evaluation of the function of a CB system. In this model test, differently from previous studies, a side drainage flow in the direction of the inclined sand layer was set as the no-flow condition; moreover, the laboratory SSCB model tests were performed by considering three rainfall intensities (i.e., 20, 50, and 100 mm/h) under the lateral no-flow condition. The results showed that the larger the rainfall intensity, the shorter the diversion length was of the CB system. To evaluate the effectiveness of the SSCB model test proposed in this study, the diversion length was estimated by an empirical equation under the lateral flow condition based on hydraulic conductivity functions and the soil water characteristic curves of sand and gravel and then compared to the results of the SSCB model tests. It was hence demonstrated that the water-shielding performance of the CB system can be efficiently evaluated through SSCB model tests under the lateral no-flow condition, rather than through large-scale model tests.

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“…In the case that fill materials are compacted or loaded, the excess pore-air pressure during compaction or loading will dissipate immediately; meanwhile, the excess pore-water pressure will dissipate with time. During and after rainfall events, the increase in pore-water pressure and volume change that is due to infiltration may result in slope instability (Tami et al 2004;Harnas et al 2016;Kim, Hwang, and Kim 2018). Therefore, the influence of matric suction on shear strength, volume change, and excess pore-water pressure has been investigated under various confining stresses and matric suctions in a triaxial apparatus (Bishop et al 1960;Blight 1961;Satija 1978;Sivakumar 1993;Fredlund and Rahardjo 1993;Wong et al 2001;Rahardjo, Ong, and Leong 2004;Meilani, Rahardjo, and Leong 2005).…”

Section: Introductionmentioning

confidence: 99%

Elastoplastic Behavior of Compacted Kaolin under Consolidated Drained and Shearing Infiltration Conditions

Kim

Rahardjo

Thang

2020

Geotechnical Testing Journal

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This study presents a comprehensive laboratory study to characterize the elastoplastic behavior of compacted kaolin under consolidated drained (CD) and shearing-infiltration (SI) triaxial conditions. The laboratory tests include a soil-water characteristic curve (SWCC), isotropic consolidation (IC), CD, and SI tests under different net confining stresses to consider in situ stress state and matric suctions that describe the volume change characteristics of unsaturated soil with respect to two stress state variables (i.e., net normal stress and matric suction).Consistently prepared specimens of statically compacted kaolin were used in this study.The results of the SWCC tests demonstrated that the air-entry value and yield suction (s o ) increased with an increase in net confining stress. The IC tests indicated the strong influence of matric suction on compressibility and stiffness of the compacted kaolin. The results of SI tests indicated that water infiltration reduced the matric suction of the soil and was accompanied by a degradation in deviator stress. It was also found from the CD and SI tests that the failure envelope of compacted kaolin was unique. For practical purposes of transient analyses, therefore, the CD and SI tests, as well as the SWCC and IC tests, might be performed to obtain more rigorously elastoplastic behavior of unsaturated soil under CD and SI conditions.

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A Physical Model for Sloping Capillary Barriers

Cited by 46 publications

References 13 publications

Effects of infiltration and evaporation on geosynthetic capillary barrier performance

Effects of infiltration and evaporation on geosynthetic capillary barrier performance

Evaluation of the Water Shielding Performance of a Capillary Barrier System through a Small-Scale Model Test

Elastoplastic Behavior of Compacted Kaolin under Consolidated Drained and Shearing Infiltration Conditions

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