Role of suction stress on service state behavior of geosynthetic-reinforced soil structures

Vahedifard, Farshid; Mortezaei, Kimia; Leshchinsky, Ben; Leshchinsky, Dov; Lu, Ning

doi:10.1016/j.trgeo.2016.02.002

Cited by 63 publications

(14 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…So, the same relationship can be expected when the friction resistance between the unsaturated soil and the geotextile is considered. Vahedifard et al [64] indicated that suction stress can significantly increase the shear strength at the contact of the soil and reinforcement, as well as can reduce the load mobilized in the geotextile.…”

Section: Shear Strength and Interfacial Friction Resistancementioning

confidence: 99%

“…Values of this coefficient were lower in case of saturated soil tests in relation to tests carried out in non-saturated conditions. Vahedifard et al [64]'s analysis of geotextile-reinforced earth structures revealed that increase in the degree of soil saturation (decrease in suction stress) affects the increase in active earth pressures and, as a result, the load of reinforcement increases. Such behaviour of the soil can be, to some extent, an explanation as to why higher values of the interaction coefficient were obtained for water-saturated samples than for unsaturated ones.…”

Section: Nonwoven Geotextilementioning

confidence: 99%

See 1 more Smart Citation

The Influence of Compaction and Water Conditions on Shear Strength and Friction Resistance between Geotextiles and Ash-Slag Mixture

2020

View full text Add to dashboard Cite

The paper presents the results of tests of the shear strength of the ash-slag mixture taken from the landfill located in Kraków (Poland) and the interfacial friction resistance at the contact between the ash-slag mixture and woven or nonwoven geotextiles. The tests were carried out in a direct shear apparatus on samples with and without water saturation. The samples for testing were formed in the apparatus box at the optimum moisture by compacting them to I S = 0.90 and 1.00. The test results reveal that the shear strength parameters of the ash-slag mixture were large. It was stated the significant influence of the compaction, the growth of which has resulted in an increase in the angle of internal friction (from 7% to 9%) and cohesion (from 60% to 97%). Whereas the saturation of the samples reduced the shear strength parameters (from 4% to 6%, of the internal friction angle and 30% to 43% of cohesion). The values of the interfacial friction resistance at the contact between the ash-slag mixture and the geotextiles were large as well, but slightly smaller than the values of the shear strength parameters of the mixture itself. The compaction caused an increase in the angle of interfacial friction (from 1% to 5%) and adhesion (from 31% to 127%). The water-saturation of the samples caused a change in the angle of interfacial friction (from −6% to 3%) and decline in the adhesion (from 22% to 69%). Values of the interaction coefficient were about 0.8-1.0 and they tended to rise with increasing the normal stress. Higher values of this parameter were obtained in tests with water saturation and for non-woven geotextiles.Another problem is the proper selection of a backfill material and its compaction. It is usually recommended to use materials with a high shear strength. As a filling, industrial wastes arising, for example, in the production of coal (coal shales), electricity or heat as a result of the coal combustion (ash slag mixtures, fly ash, slag, microsphere, ashes from the fluidized furnace) are also increasingly used. Wastes are generated in the combustion processes because there are large amounts of non-flammable substances, their content in coal ranges from 11% to 17% (hard coal extracted in Poland) and from 3% to 11% (lignite) [8]. The by-products of combustion can be used as artificial aggregates in earth structures [8][9][10][11]. The utilisation of these products in earth structures is of great importance from the economic and ecological points of view. The use of artificial aggregates and geosynthetics for strengthening the soil subgrade also has a significant impact on the protection of natural aggregates. It makes possible constructing the embankments of the selected industrial wastes and limits the scope of soil exchange.In order to meet current requirements for earthworks, the use of geosynthetics that satisfy the requirements for acceleration and quality of works, as well as the optimization of costs of road pavement construction, have been started [12]. In addition to the versatility of using geosynt...

show abstract

Section: Shear Strength and Interfacial Friction Resistancementioning

confidence: 99%

Section: Nonwoven Geotextilementioning

confidence: 99%

The Influence of Compaction and Water Conditions on Shear Strength and Friction Resistance between Geotextiles and Ash-Slag Mixture

2020

View full text Add to dashboard Cite

show abstract

“…5, if conditions are too wet (e.g., extreme rainfall events), or inversely, too dry (e.g., drought) the air-water interface areas in soil will diminish, resulting in very small to zero suction stress, and smaller shear stress than as seen between 0 % < S e < 100 %. Such changes in suction stress and shear strength can significantly impact the stability of natural and man-made earthen structures such as levees (e.g., Lu and Likos 2006;Vahedifard et al 2015bVahedifard et al , 2016c. Figure tensile strength characteristic curve (TSCC) and the soil water characteristic curve (SWCC) for the same three representative sands.…”

Section: Horizontal Translationmentioning

confidence: 99%

Weakening mechanisms imposed on California’s levees under multiyear extreme drought

Robinson

Vahedifard

2016

Climatic Change

Self Cite

View full text Add to dashboard Cite

California is currently suffering from a multiyear extreme drought and the impacts of the drought are anticipated to worsen with climate change. The resilience of California's critical infrastructure such as earthen levees under drought conditions is a major concern that is poorly understood. California maintains more than 21,000 km of urban and nonurban levees which protect dry land from floods and deliver two-thirds of the state's drinking water. Many of these levees are currently operating under a high failure risk condition. This essay argues that California's protracted drought can further threaten the integrity of these already at-risk levee systems through the imposition of several thermo-hydro-mechanical weakening processes. Pertinent facts and statistics regarding California's drought and current status of its levees are presented. Lessons from previous catastrophic levee failures and major damages which occurred under similar events are discussed. Weakening processes such as soil-strength reduction, soil desiccation cracking, land subsidence and surface erosion, and microbial oxidation of soil organic carbon are comprehensively evaluated to illustrate the adverse impacts that the ongoing California drought can have on levees. This essay calls for further research in light of these potential droughtinduced weakening mechanisms to support adaptation and mitigation strategies to possibly avert future levee failures. These weakening processes can threaten any drought-stricken infrastructure interfacing with soil, including embankments, roads, bridges, building foundations, and pipelines.

show abstract

“…Cohesion should be accounted for design purposes with great caution and only when its value can be reliably assessed during the life span of the slope (e.g., in cemented soils or native soils). Several design guidelines do not recommend use of cohesion in design, primarily due to significant uncertainties associated with the determination of a reliable apparent cohesion value as well as its tendency to vanish with a change in the degree D r a f t 6 of saturation (e.g., Leshchinsky and Tatsuoka 2013;Vahedifard et al 2014;Vahedifard et al 2016b). Fig.…”

Section: Formulation and Proposed Frameworkmentioning

confidence: 99%

Optimal profile for concave slopes under static and seismic conditions

2016

Self Cite

View full text Add to dashboard Cite

This study presents a methodology to determine the stability and optimal profile for slopes with concave cross section under static and seismic conditions. Concave profiles are observed in some natural slopes suggesting that such geometry is a more stable configuration. In this study, the profile of a concave slope was idealized by a circular arc defined by a single variable, the mid-chord offset (MCO). The proposed concave profile formulation was incorporated into a limit equilibrium–based log spiral slope stability method. Stability charts are presented to show the stability number, MCO, and mode of failure for homogeneous slopes corresponding to the most stable configuration under static and pseudostatic conditions. It is shown that concave profiles can significantly improve the stability of slopes. Under seismic conditions, the impact of concavity is most pronounced. Good agreement was demonstrated upon comparison of the results from the proposed method against those attended from a rigorous upper bound limit analysis. The proposed methodology, along with recent advances in construction technology, can be employed to use concave profiles in trenches, open mine excavations, earth retaining systems, and naturally cemented and stabilized soil slopes. The results presented provide a useful tool for preliminary evaluation for adopting such concave profiles in practice.

show abstract

Role of suction stress on service state behavior of geosynthetic-reinforced soil structures

Cited by 63 publications

References 34 publications

The Influence of Compaction and Water Conditions on Shear Strength and Friction Resistance between Geotextiles and Ash-Slag Mixture

The Influence of Compaction and Water Conditions on Shear Strength and Friction Resistance between Geotextiles and Ash-Slag Mixture

Weakening mechanisms imposed on California’s levees under multiyear extreme drought

Optimal profile for concave slopes under static and seismic conditions

Contact Info

Product

Resources

About