Experimental evaluation of mechanical behavior of unsaturated silty sand under constant water content condition

Maleki, Mohammad; Bayat, Meysam

doi:10.1016/j.enggeo.2012.04.014

Cited by 38 publications

(11 citation statements)

References 26 publications

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“…The OMC and maximum dry density are parameters which are usually used in construction projects such as road and railway embankments, landfill liners, backfills of retaining structure and earth dams, so understanding of the dynamic properties of soil in these conditions are important. The wet-tamping technique is the oldest technique which is used for preparing unreinforced and reinforced soil specimens and has been widely used by previous researchers (Behavior and Symposium, 2006;Escribano and Nash, 2015;Flora and Lirer, 2013;Gu et al, 2015;Maleki and Bayat, 2012). The wet-tamping technique can model the soil fabric of (Czajkowski and Vinson, 1980;Di Donna et al, 2016;Zhao et al, 2014;Zhu et al, 2011).…”

Section: Specimen Preparation and Freeze-thaw Cyclesmentioning

confidence: 99%

Shear modulus and damping ratio of clay soil under repeated freeze-thaw cycles

Roustaei¹

2021

Acta Geodynamica Et Geomaterialia

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The dynamic properties of soil deposits subjected to dynamic loading, such as the shear modulus G and material damping ratio D, are important parameters in ground response seismic analysis. In seasonally frozen regions, these properties can be significantly affected by microstructural changes that occur during freeze-thaw cycles. The current study evaluated the dynamic properties of clayey soil exposed to freeze-thaw cycles. Dynamic triaxial testing was conducted to determine the influence of mean effective consolidation stress, cyclic stress ratio, loading frequency, and freeze-thaw cycles on G-γ and D-γ curves. Scanning electron microscopy (SEM) was carried out to investigate microstructural changes in the clay soil fabric. The results indicate the freeze-thaw process has an important effect on dynamic properties of the soil. The dynamic shear modulus increases with increasing effective confining pressure, loading frequency, and confining pressure, and decreases with increasing number of freeze-thaw cycles. Development of more voids between clay particles after ice lens formation during these cycles results in an increase in the damping ratio, but this trend decreases with increasing confining pressure. Increasing the loading frequency increases or decreases the damping ratio depending upon the mean effective confining pressure and number of freeze-thaw cycles.

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Section: Specimen Preparation and Freeze-thaw Cyclesmentioning

confidence: 99%

Shear modulus and damping ratio of clay soil under repeated freeze-thaw cycles

Roustaei¹

2021

Acta Geodynamica Et Geomaterialia

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“…The aim of group 1 testing was to examine the effect of grading characteristics, D r and σ′ m on dynamic properties. In this group of the tests, the WT method was used with a low initial moisture content and consideration of under-compaction of the lower layers during preparation which has the advantage of easy control of void ratio (Ladd, 1987;Maleki and Bayat, 2012). The results show that the effect of σ′ m on the dynamic properties is more significant than the effect of grading characteristics and D r .…”

Section: Curvesmentioning

confidence: 99%

Universal model forms for predicting the dynamic properties of granular soils

Bayat¹

2020

Acta Geodynamica Et Geomaterialia

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Dynamic soil properties are important parameters for the design of structures subjected to various dynamic/cyclic loading such as earthquake which can be obtained by in situ and laboratory measurements. Numerous empirical and mathematical models have been proposed to predict the dynamic properties of soils, including maximum shear modulus (G max), normalized shear modulus (G/G max-γ) curve, reference shear strain (γ r), minimum damping ratio (D min) and damping ratio (D-γ) curve. However, the majority of the existing models were proposed for specific soil types, loading characteristics, initial soil fabrics and strain ranges. This paper proposes five universal models to estimate the G max , γ r and D min values, and also G/G max-γ and D-γ curves using a database that contains 117 tests on 5 different granular soils. The proposed models include the effect of grading characteristics, void ratio, mean effective confining pressure, consolidation stress ratio (K C) and specimen preparation method. The models are validated using experimental data from previous studies for granular soils. The results indicate that the proposed models are capable of evaluating the dynamic properties of granular soil.

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“…Many researchers and studies [3]- [8] investigated the laboratory mechanical behavior of collapse soil and reported that the major soil categories that lead to substantial collapse involved filling and soil classified as CL and ML soils, conferring to the Unified Soil Classification System, and also, soil deposit which has a low initial dry density, low moisture content and low plasticity, susceptible collapse [8] [9] [10]. ASTM D5333-92 defines a "collapse index (I e )" as the deferential vertical strain between the wet and dry conditions at a pressure of 200 kPa [6] [11].…”

Section: Introductionmentioning

confidence: 99%

Practical Engineering Behavior of Egyptian Collapsible Soils, Laboratory and <i>In-Situ</i> Experimental Study

Ali¹

2021

OJCE

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In many sites on Egypt desert roads collapsible soils is broadly classified as a problematic soils containing silty fine sand which is cemented with low density and low degree of saturation which is susceptible to a large and sudden reduction in their volume upon inundation, with or without vibration in its stress. Four sites have been studied for new urban, roads and industry work sits, related to increase in natural water content. These soils go through radical rearrangement of their particles, causing sudden changes in the stress-deformation behavior which cause differential settlement of foundation and roads. This change in volume can lead to foundation failures and worth of damages under ground public facilities and infrastructure. In this study, the search program is developed to establish their different behavior under wetting in two phases: field and laboratory work. The obtained results are useful in mapping the trend of the factors affected in assessing soil collapsibility rate or collapse potentials which are observed in construction with volume change problems. The major factors observed are the natural structure skeleton of the soil particle and its grain size and mechanism of soil sedimentation. The field collapse potentials value assigned for these tested sites along Alexandria-Cairo desert road indicated that the field measured collapsibility potentials are smaller than those measured on the same extracted undisturbed samples in laboratory by 15%, which can be saved in coast, change in proposed collapsibility improvement method and change in select foundation type. Also, field tests evaluate the collapsibility rate with time and highlight that environmental history and natural soil structure in field are the important factors affected on these soil collapse, and also, knowledgeable by collapsible soils during wetting in these sites studied.

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Experimental evaluation of mechanical behavior of unsaturated silty sand under constant water content condition

Cited by 38 publications

References 26 publications

Shear modulus and damping ratio of clay soil under repeated freeze-thaw cycles

Shear modulus and damping ratio of clay soil under repeated freeze-thaw cycles

Universal model forms for predicting the dynamic properties of granular soils

Practical Engineering Behavior of Egyptian Collapsible Soils, Laboratory and <i>In-Situ</i> Experimental Study

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Experimental evaluation of mechanical behavior of unsaturated silty sand under constant water content condition

Cited by 38 publications

References 26 publications

Shear modulus and damping ratio of clay soil under repeated freeze-thaw cycles

Shear modulus and damping ratio of clay soil under repeated freeze-thaw cycles

Universal model forms for predicting the dynamic properties of granular soils

Practical Engineering Behavior of Egyptian Collapsible Soils, Laboratory and &lt;i&gt;In-Situ&lt;/i&gt; Experimental Study

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Product

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Practical Engineering Behavior of Egyptian Collapsible Soils, Laboratory and <i>In-Situ</i> Experimental Study