Microstructural investigation on mechanical behavior of soil-geosynthetic interface in direct shear test

Punetha, Piyush; Mohanty, Piyush; Samanta, Manojit

doi:10.1016/j.geotexmem.2017.02.001

Cited by 70 publications

(22 citation statements)

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“…The analysis of Figures 4-6 shows that the interfacial friction resistance values were lower than the shear strength of the ash-slag mixture. This phenomenon was also found by Vieira et al [65] and Punetha et al [6], who indicated that this is most likely the result of loosening the soil over the geotextiles, due to the suppression of soil settlement by it. This relation may also result from the surface roughness of geotextiles and their surface mass.…”

Section: Shear Strength and Interfacial Friction Resistancesupporting

confidence: 77%

“…The parameters of the shear strength of the ash-slag mixture and the friction resistance at the contact of the mixture and the nonwoven or woven geotextiles were large. The influence of moisture content and the compaction of sand on shear strength values was also analyzed in detail by Punetha et al [6]. While comparing the results of the research on dry sand and partially saturated sand, these authors stated that in unsaturated soil, the friction between grains and reinforcement occurs more often than when the soil is dry.…”

Section: Discussionmentioning

confidence: 99%

“…where E c (%) is the effectiveness of strengthening with geosynthetic due to cohesion, E ϕ (%) is the effectiveness of strengthening with geosynthetic due to friction resistance, c a (kPa) is the adhesion between the soil and geosynthetic, c (kPa) is the soil cohesion, δ ( • ) is the angle of interfacial friction, and ϕ ( • ) is the angle of internal friction of the soil. The comparison of test results of soil shear strength parameters and friction parameters on the interface between soil and geosynthetic [4,6,[52][53][54] indicates that the values of the parameters E ϕ and E c are within a wide range (from 0.41 to 1.15 and from 0.45 to 1.41, respectively), but they are generally smaller than the value of 1.0. However, it should be noted that the usefulness of the E c parameter seems disputable (questionable) in the case when tested soil is non cohesive.…”

Section: Introductionmentioning

confidence: 99%

“…The mechanism of interaction between the reinforcement and the surrounding soil has been determined by many researchers, most often in laboratory conditions (e.g., [1][2][3][4]). The phenomenon of interaction takes place in a thin layer of soil close to the reinforcement and depends on a number of complex phenomena in this layer [5][6][7], such as the physical properties of the soil (e.g., angularity of soil particles, relative density and degree of saturation) and geotextiles (e.g., roughness, hardness), as well as the testing conditions (e.g., testing method, dimensions of sample, boundary conditions) [6,7]. contact with the reinforcement.…”

Section: Introductionmentioning

confidence: 99%

“…The effect of soil compaction on its shear strength is well known. On the other hand, the results of friction resistance tests (among others [6,52]) indicate that the impact of compaction is not always clear and depends on the type of backfill and geotextile. Another engineering problem that occurs is related to the exploitation conditions.…”

Section: Introductionmentioning

confidence: 99%

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

2020

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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...

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Section: Shear Strength and Interfacial Friction Resistancesupporting

confidence: 77%

Section: Discussionmentioning

confidence: 99%