scholarly journals Experimental Study on Normal Frost-Heave Force Generated from Loess upon Freezing considering Multiple Factors

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Zai-kun Zhao ◽  
Tie-hang Wang ◽  
Xin Jin ◽  
Yu Zhang
Keyword(s):  
Experimental Study ◽  
Water Content ◽  
Freezing Temperature ◽  
Frost Heave ◽  
Dry Density ◽  
Force Model ◽  
Test Results ◽  
Multiple Factors ◽  
Water Contents ◽  
Good Agreement

An experimental study on the normal frost-heave force generated by loess was conducted by subjecting loess with various water contents and densities to different temperature conditions. The experimental results show that the interaction of the three factors has a significant effect on the normal frost-heaving force. Normal frost-heave force increases exponentially with an increase in dry density and linearly with a reduction in the freezing temperature or an increase in water content; of these factors, dry density has the greatest influence on frost-heave force, followed by water content then temperature. A frost-heave force model is developed that includes overall consideration of the interactions of water content, density, and temperature based on fitting of the test results. The value calculated with the model is in good agreement with values measured in verification tests, indicating that the model has high accuracy and can provide scientific guidance for engineering design in loess areas.

Compacted soil behaviour through changes of density, suction, and stiffness of soils with remoulding water content

2018 ◽  
Vol 55 (2) ◽  
pp. 182-190 ◽  
Author(s):  
T.W. Zhang ◽  
Y.J. Cui ◽  
F. Lamas-Lopez ◽  
N. Calon ◽  
S. Costa D’Aguiar
Keyword(s):  
Water Content ◽  
Dry Density ◽  
Soil Plasticity ◽  
Optimum Water Content ◽  
Hydromechanical Behaviour ◽  
The Difference ◽  
Two Peaks ◽  
Soil Behaviour ◽  
Optimum Water ◽  
Water Contents

To better understand the overall hydromechanical behaviour of interlayer soil, the compaction behaviour of one of the two components — the portion of fines (<4 mm) that is sensitive to water content changes — was investigated. The standard Proctor compaction curves were first determined for the soils. Then, the maximum shear modulus, Gmax, and suction were measured on samples statically compacted at an identical dry density, but different remoulding water contents. The changes in Gmax reveal the existence of a characteristic water content corresponding to the maximum Gmax. The results also show that this characteristic water content increases with the soil plasticity, being similar to the variation trend of optimum water content with soil plasticity. A bimodal pattern was observed from the plot of total suction ψ versus the slope of water content w–log(ψ) curve. The suction corresponding to the maximum Gmax is close to the lowest point between the two peaks in the ψ–dw/dlog(ψ) curve. A reasonable explanation was attempted for the correspondence between the “optimum water content” defined by the maximum value of Gmax and the corresponding suction. The difference between the static and dynamic compactions was also explained in terms of suction values.

Impact of density on the hydraulic properties of peat and the time domain reflectometry (TDR) moisture calibration curve

2005 ◽  
Vol 42 (1) ◽  
pp. 279-286 ◽  
Author(s):  
Anushka Shibchurn ◽  
Paul J Van Geel ◽  
Paula L Kennedy
Keyword(s):  
Dielectric Constant ◽  
Soil Moisture ◽  
Water Content ◽  
Time Domain ◽  
Calibration Curve ◽  
Hydraulic Properties ◽  
Time Domain Reflectometry ◽  
Organic Soils ◽  
Dry Density ◽  
Water Contents

The hydraulic properties of a peat used in a commercial peat biofilter were evaluated to determine their relationship with density and to establish a time domain reflectometry (TDR) calibration curve for water content as a function of the measured dielectric constant. The peat studied was a milled Sphagnum peat with a high organic content (99%). The dry densities evaluated in this study ranged from 90 to 180 kg/m3. The saturated hydraulic conductivity (Ks) decreased with an increase in dry density (ρdry) and was found to follow a log-linear relationship (Ks = 0.2462 exp(–0.0438ρdry), correlation coefficient R2 = 0.9789). As expected, the soil moisture curve was impacted by density, with a higher density resulting in higher water contents for a given suction. The data were fit to the van Genuchten relationship. A TDR calibration curve was generated at five different densities. A comparison of the curves indicates that the water content as a function of dielectric constant was not dependent on density because of the significantly larger dielectric constant (Ka) of water compared with those of peat solids and air-filled voids. The TDR calibration curve for the peat evaluated in this study (volumetric water content Θv = 0.2667 ln(Ka) – 0.1405, R2 = 0.9564) predicted higher water contents for a given dielectric constant compared with those from similar calibration curves for peat published in the literature. The data were compared with those from six other studies and indicated that the TDR calibration varied for different organic soils. The density-dependent hydraulic parameters and TDR calibration curve are important parameters needed to study the hydraulics of peat biofilters.Key words: peat, TDR, time domain reflectometry, density, hydraulics, soil moisture.

scholarly journals Experimental Study of the Bending Strength of Recycled Concrete and Wooden Waste by Heating Compaction

2020 ◽  
Author(s):  
Liang Li ◽  
Yuya Sakai
Keyword(s):  
Experimental Study ◽  
Water Content ◽  
Bending Strength ◽  
Recycled Concrete ◽  
New Approach ◽  
Ordinary Concrete ◽  
Mixture Pressure ◽  
The World ◽  
Recycle Concrete ◽  
Water Contents

A large amount of concrete waste is generated around the world and its recycling is an urgent issue. In this research, a new approach to recycle concrete waste with wooden waste was studied. Concrete and wooden wastes were crushed, mixed, and heat compacted to produce plates with different water contents and mix proportions at various temperatures, pressures, and durations of compaction. The bending strength of the plates was measured after compaction. The result indicated that with an increase in the percentage of wooden waste in the mixture, pressure, or temperature improved the bending strength. The increase in water content reduced the bending strength. Most of the products exhibited higher bending strength than that of ordinary concrete.

scholarly journals Physical and Mechanical Characteristics of Shallow Expansive Soil due to Freeze-Thaw Effect with Water Supplement

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yanlong Li ◽  
Zili Wang ◽  
Yang Luo
Keyword(s):  
Shear Strength ◽  
Water Content ◽  
Expansive Soil ◽  
Freezing Temperature ◽  
Strength Reduction ◽  
Dry Density ◽  
Direct Shear ◽  
Soil Columns ◽  
Freeze Thaw ◽  
Shear Strength Reduction

Shear strength of shallow expansive soil varies along with the depth under the freeze-thaw effect. This work investigates shear strength characteristics of shallow expansive soil by simulating the actual freeze boundary conditions of seasonal frozen areas with water supplement. An integrated approach incorporating the freeze-thaw test and direct shear test was adopted. Firstly, unidirectional freezing tests for expansive soil columns under three different freezing temperature gradients were carried out. Secondly, direct shear tests under low vertical stress were performed on the standard samples, which were prepared by using cutting rings cut the thawed expansive soil columns into nine segments along with the depth. Temperature, water content, and dry density at different depths were also investigated after the freeze-thaw process. The test results showed that, after the freeze-thaw process, the shear strength of expansive soil columns showed significant differences along with the depth and highly correlated with water content, specifically the higher water content and the lower shear strength. The minimum shear strength in the expansive soil columns occurred at the soil layer below the frozen and unfrozen zones interface. The expansive soil column’s shear strength changed most under the moderate freezing temperature gradient corresponding to the most considerable shear strength reduction. Moreover, the significant decrease in cohesion was the main reason for the shear strength reduction of expansive soil after the freeze-thaw process. These results indicate significant depth variability in shear strength of expansive soil under the freeze-thaw effect.

Experimental Study on Dewatering Dredged Clay with Ventilating Vacuum Method

2011 ◽  
Vol 261-263 ◽  
pp. 1650-1654 ◽  
Author(s):  
Feng Ji ◽  
Jian Wen Ding ◽  
Zhen Shun Hong ◽  
Yue Gui
Keyword(s):  
Experimental Study ◽  
Spatial Distribution ◽  
Surface Water ◽  
Water Content ◽  
Liquid Limit ◽  
Initial Water Content ◽  
Distribution Law ◽  
Initial Water ◽  
Vacuum Method ◽  
Water Contents

A series of model tests were performed on dredged clay with high initial water contents for investigating the dewatering behavior by ventilating vacuum method (VVM). The results shows that the surface water separated from dredged clay can be quickly removed by VVM in which a new pattern PVD is used. In addition, the method also speeds up the deposition of dredged clay. The volume of dredged clay with an initial water content of 4.5 times liquid limit decreases by 50 percent within two months. This paper also investigated the spatial distribution law of water content by TDR method. It is found that the drainage distance of PVD is about 0.3-0.4m.

Experimental Study on the Improvement of High Water Content Dredged Material by Cement and by Quicklime

2014 ◽  
Vol 878 ◽  
pp. 714-719 ◽  
Author(s):  
Ying Hao Huang ◽  
Chan Dong ◽  
Xiao Lei Zhan ◽  
Yun Fei Guan
Keyword(s):  
Water Content ◽  
High Water ◽  
High Water Content ◽  
Dry Density ◽  
Dredged Material ◽  
Test Results ◽  
Environmental Friendly ◽  
Dredged Materials ◽  
Beneficial Uses ◽  
Modified Soil

Dredging is necessary to keep rivers, harbors and lakes function normally. These dredged materials (DM) have poor geotechnical properties and are normally treated as wastes. Thus, utilization of DM for beneficial uses such as fill is being considered as an environmental-friendly and economical option. In this study a dredged material taken from Tai-hu Lake was modified by adding quicklime and by Portland cement. Water content, dry density, plasticity, and California bearing ratio (CBR) of the two types of modified soil were determined and compared. Test results show that both quicklime and cement can evidently decrease the water content and increase dry density, but the former can get better effect relatively. On the other hand, both quicklime and cement can significantly decrease the plasticity characteristics, and change the raw DM classified as CH to MH after modified, moreover, the cement has better effect on the improvement of plasticity. For the same additive content and curing days, the cement modified soil has larger CBR strength than that of the quicklime modified soil. Conclusions of the paper maybe beneficial and useful for the solidification material choose, and for practical dredged material solidification projects.

The Effects of Water Content towards the Packaging Properties of Paper Made from Coconut Coir

2013 ◽  
Vol 315 ◽  
pp. 161-165
Author(s):  
Mohd Hilmi Othman ◽  
Sulaiman Hasan ◽  
Md Zin Ibrahim
Keyword(s):  
Tensile Strength ◽  
Water Content ◽  
Manufacturing Industry ◽  
Test Results ◽  
Paper Manufacturing ◽  
Coir Fibre ◽  
Breaking Length ◽  
Coconut Coir ◽  
Coconut Fibre ◽  
Water Contents

This research is about an attempt to evaluate the effect of water contents towards the packaging properties of paper made from coconut coir, which was being processed manually through beating times method. The purpose of this investigation is to relate the composition of coconut fibre and water content with the tensile strength and tear factor. The composition starts from sample A, which has 90% of water and 10% of coconut fibre. The sample continues with 10% decreasing content of water and 10% increment of coconut coir. Base on tensile test and tear test results, graphs were plotted and it shows sample D, with 60% of water and 40% of coconut coir has produced the highest tensile strength, breaking length and tensile index, with the value of 1020.6 N/m, 422.8 m and 4.1450 Nm/g respectively. On the other hand, sample A produced the highest tear factor, with the value of 92.7 g/mm2. As a conclusion, these packaging properties are good enough to become guidance in paper manufacturing industry, as well as to support the application of coconut coir fibre as an alternative packaging material in the future.

Density Influence on Matric Suction of the Eolian Sand under the Condition of Loop of Dehumidifying and Humidifying Process

2011 ◽  
Vol 250-253 ◽  
pp. 2157-2160
Author(s):  
Yan Xun Song ◽  
Qiang Xu ◽  
Xi An Li ◽  
Hong Zhou Lin
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Matric Suction ◽  
Dry Density ◽  
Test Results ◽  
Unsaturated Sand ◽  
Water Characteristics ◽  
Eolian Sand ◽  
The Relationship ◽  
Variation Tendency

The matric suction has very important influence on the characteristics of unsaturated sand; and it is closely relevant to density. In order to discuss the relationship among the matric suction, water content and dry density, the matric suction of the eolian sand were measured in laboratory. The soil-water characteristics curves for unsaturated eolian sand with different dry densities are obtained. The test results show that the variation tendency of soil-water characteristics curves has been corresponding to the different densities.

scholarly journals Exudate coloring test suitability for assessing the viability of coffee seeds ( Coffea arabica L.)

2016 ◽  
Vol 38 (3) ◽  
pp. 212-218 ◽  
Author(s):  
Paulo César Hilst ◽  
Denise Cunha Fernandes dos Santos Dias ◽  
Guilherme Fontes Valory Gama ◽  
Joyce de Oliveira Araújo
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
Coffea Arabica ◽  
Test Results ◽  
Germination Test ◽  
Paper Towel ◽  
Coffea Arabica L ◽  
Water Contents

Abstract: The exudate coloring test has been promising in order to quickly evaluate the quality of coffee seeds. The objective of the research was to adjust the coloring exudate test for coffee seeds and to evaluate the influence of the water content of seeds and of the imbibition period on the test results. Seeds from five lots of 'Catuaí 44' were used, with the following water contents: 30%, 20% and 12%. For the exudate coloring test, the parchment and silver skin (spermoderm) from the seeds were removed. Then, the seeds were distributed on a paper towel, moistened with water, and kept in a germinator at 25 °C for 24, 48, 72, 96 and 120 h. Four classes of coloring intensity were established: absence of color (A), light (L), medium (M) and strong (S) intensities, assigning the values 0, 3, 5 and 10 for each class, respectively. The Viability Index (VI) was calculated by the equation VI=100-(0xA)-(3xL)-(5xM)-(10xS). The exudate coloring test may be recommended to estimate the viability of coffee seeds, providing results correlated to the germination test. The best results were obtained for the seeds with 12% moisture content imbibed for 72, 96 and 120 h and seeds with 30% moisture content after 72 and 120 h of imbibition.

scholarly journals Softening of Temperate Ice by Interstitial Water

2021 ◽  
Vol 9 ◽  
Author(s):  
Conner J. C. Adams ◽  
Neal R. Iverson ◽  
Christian Helanow ◽  
Lucas K. Zoet ◽  
Charlotte E. Bate
Keyword(s):  
Experimental Study ◽  
Water Content ◽  
Effective Viscosity ◽  
Tertiary Creep ◽  
Secondary Creep ◽  
Confined Compression ◽  
Grain Sizes ◽  
West Antarctic ◽  
Water Films ◽  
Water Contents

Ice at depth in ice-stream shear margins is thought to commonly be temperate, with interstitial meltwater that softens ice. Models that include this softening extrapolate results of a single experimental study in which ice effective viscosity decreased by a factor of ∼3 over water contents of ∼0.01–0.8%. Modeling indicates this softening by water localizes strain in shear margins and through shear heating increases meltwater at the bed, enhancing basal slip. To extend data to higher water contents, we shear lab-made ice in confined compression with a large ring-shear device. Ice rings with initial mean grain sizes of 2–4 mm are kept at the pressure-melting temperature and sheared at controlled rates with peak stresses of ∼0.06–0.20 MPa, spanning most of the estimated shear-stress range in West Antarctic shear margins. Final mean grain sizes are 8–13 mm. Water content is measured by inducing a freezing front at the ice-ring edges, tracking its movement inward with thermistors, and fitting the data with solutions of the relevant Stefan problem. Results indicate two creep regimes, below and above a water content of ∼0.6%. Comparison of effective viscosity values in secondary creep with those of tertiary creep from the earlier experimental study indicate that for water contents of 0.2–0.6%, viscosity in secondary creep is about twice as sensitive to water content than for ice sheared to tertiary creep. Above water contents of 0.6%, viscosity values in secondary creep are within 25% of those of tertiary creep, suggesting a stress-limiting mechanism at water contents greater than 0.6% that is insensitive to ice fabric development in tertiary creep. At water contents of ∼0.6–1.7%, effective viscosity is independent of water content, and ice is nearly linear-viscous. Minimization of intercrystalline stress heterogeneity by grain-scale melting and refreezing at rates that approach an upper bound as grain-boundary water films thicken might account for the two regimes.

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