SOIL WATER CHARACTERISTIC CURVES OF COMPACTED KAOLIN FOR VARIOUS INITIAL MOISTURE CONTENT

2015 ◽  
Vol 76 (2) ◽  
Author(s):  
Muhammad Azril Hezmi ◽  
Radzuan Saari ◽  
Mohd Zakri Zahari ◽  
Rini Asnida Abdullah ◽  
Nor Zurairahetty Mohd Yunus ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Filter Paper ◽  
Unsaturated Soils ◽  
Initial Moisture Content ◽  
Great Influence ◽  
Water Retention Curve ◽  
Initial Water Content ◽  
Initial Water ◽  
The Relationship

The soil water characteristic curve (SWCC), also known as soil water retention curve (SWRC), describes the relationship between water content and soil suction in unsaturated soils. The importance of SWCC can be seen, as the relationship affects geotechnical properties such as shear strength, volume change, permeability and deformability of unsaturated soils. This paper presented a preliminary study on the effect of initial water content and the density on SWCC on unsaturated compacted kaolin. Filter paper technique was used for suction measurement on the unsaturated compacted kaolin soil. Filter paper was used to determine total suction and matric suction through contact and noncontact technique. The calibration curve was used to relate with the gravimetric water content obtained in filter paper with corresponding suction. A comparison on SWCC established through filter paper was also compared with that of the axis translation technique (pressure plate extractor). The study found that the initial water content and the density respectively, have great influence on the SWCC of compacted kaolin. However, the combined effect could be seen significantly at lower suction

Measurement of SWCC of Xiamen Residual Soil by Filter Paper

2012 ◽  
Vol 256-259 ◽  
pp. 1046-1051
Author(s):  
Dong Xia Chen ◽  
Ma Xiu Zhang ◽  
You Qiang Lin ◽  
Jian Ni
Keyword(s):  
Hysteresis Loop ◽  
Water Content ◽  
Filter Paper ◽  
Unsaturated Soils ◽  
Experimental Program ◽  
Initial Water Content ◽  
Residual Soil ◽  
Soil Specimen ◽  
Initial Water ◽  
Significant Difference

Soil suction is one of the most important parameters for unsaturated soils. An experimental program was carried out to measure the maric suction of soil specimens of a residual soil in Xiamen by filter paper method. Initial water content, soil structure, and stress state were taken into account to investigate the hysteresis loop of SWCC. The air-entry value of test soil is about 140kPa and residual saturation is about 18%. The soil specimen at wet of optimum has the largest hysteresis loop for a relatively uniform pore-size distribution. However, the soil specimen at dry of optimum has the smallest hysteresis loop. The soil specimen at optimum lies between them. For specimens subjected to different stress states under various applied loads, the higher the applied load on the specimen, the smaller the size of hysteresis loop. In drying or wetting process, there is a significant difference in matric suction though soil specimens are at same water content. Therefore, for this kind of soil, it should be attention that the shear strength may be greatly reduced during rainstorms.

scholarly journals Alternative Method for Analysing Hydromechanical Behaviour of Unsaturated Soils

2016 ◽  
pp. 29-39
Author(s):  
Márcia Maria dos Anjos Mascarenha ◽  
Manoel Porfírio Cordão Neto ◽  
Tâmara Moraes Guimarães Silva
Keyword(s):  
Water Content ◽  
Unsaturated Soils ◽  
Soil Mechanics ◽  
Water Retention Curve ◽  
Initial Water Content ◽  
High Porosity ◽  
Initial Water ◽  
Suction Control ◽  
Alternative Method ◽  
Hydromechanical Behaviour

The suction-control techniques commonly used for laboratory studies of mechanical behaviour of unsaturated soils are much more time consuming than standard soil mechanics tests. In addition, few laboratories have the required apparatus for testing unsaturated soils. This paper proposes an alternative method of analysing hydromechanical behaviour of unsaturated soils with high-porosity. The method is divided in three tasks: 1) verification of the effect of void ratio changes on the water retention curve using filter paper; 2) determining water content changes by evaporation under the same test conditions; and 3) performing saturated and unsaturated consolidation tests. Unsaturated tests make use of samples that are less than 100% saturated and there is no suction control during the test. Therefore, only initial water content is known. Significant suction changes take place due to void closure and evaporation while testing. The results obtained using the proposed methodology showed the stress and suction path and enhance the understanding of the hydromechanical behaviour of unsaturated soils. The results also showed that analyses of water content alone cannot explain some unexpected results, such as: 20% initial water content samples present less deformation than 16% samples.

Determination of the tensile strength of unsaturated tailings using bending tests

2015 ◽  
Vol 52 (11) ◽  
pp. 1874-1885 ◽  
Author(s):  
Bibiana Narvaez ◽  
Michel Aubertin ◽  
Faustin Saleh-Mbemba
Keyword(s):  
Tensile Strength ◽  
Water Content ◽  
Water Retention ◽  
Water Retention Curve ◽  
Initial Water Content ◽  
Ambient Conditions ◽  
Initial Water ◽  
Bending Tests ◽  
Retention Curve ◽  
Apparent Cohesion

Bending tests were conducted on specimens of unsaturated tailings from three hard rock mines to evaluate their tensile strength. Saturated samples were prepared at an initial water content, w0, of 40% and then naturally dried under ambient conditions to pre-selected degrees of saturation, Sr, which can be related to the corresponding suction using the water retention curve. The basic interpretation of the bending tests results is based on an elastic–brittle behavior. The results show how the tensile strength, σt, of unsaturated tailings varies with water content, w (and Sr). The experimental data are also used to evaluate Young’s modulus in tension, Et, and to estimate the apparent cohesion, capp, as a function of Sr. Predictive equations are also applied to estimate the values of σt of unsaturated tailings using the water retention curve.

scholarly journals Initial Moisture Content of Corncobs Plays an Important Role in Maintaining its Quality during Storage

2018 ◽  
Vol 38 (2) ◽  
pp. 167
Author(s):  
Lince Mukkun ◽  
Herianus J.D. Lalel ◽  
Yuliana Tandirubak
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
Insect Pests ◽  
Initial Moisture Content ◽  
High Water ◽  
High Water Content ◽  
Initial Water Content ◽  
Initial Water ◽  
Plant Materials ◽  
Randomized Design

Maize is one of the important staple foods for people in Timor, East Nusa Tenggara Province, Indonesia. Subsistent farmers store the maize for their own consumption until the next harvest season, for seed and feed.  However, high initial water content of the kernel due to improper drying prior storage initiate serious damage and losses during the maize storage.  High water content promotes the growth of fungi and insects, and increase respiration rate, resulting in rapid deterioration of maize. The purpose of this study was to determine the initial moisture content that might minimize damage and losses of maize in the farmers’ storage, and to study the effects of some plant materials that are used to smoke corns before storage. The experiment was initiated by sun-drying the harvested corncobs for 0, 2, 4, 6, 8, and 10 days (6 hours a day). This experiment was designed using Completely Randomized Design with 6 treatments and 3 replications. Dried corncobs were stored in the farmer’s storage for 4 months. The effects of maize kernels’ initial water content on the development of water content in kernels; the percentage of damaged kernels; and the species of pathogen and insects were investigated during storage with 2-week intervals.  The results demonstrated that drying the corncobs prior storage for 10 days, resulting in 12.96% of water content, significantly decreased the percentage of seed damage to 6.5%, as compared to without drying process which resulted  in 63%.  Aspergillus flavus, Fusarium sp., and Penicillium sp were found to be the main pathogen during storage.  There are no insect pests found during the storage. 

scholarly journals Effect of initial gravimetric water content and cyclic wetting-drying on soil-water characteristic curves of disintegrated carbonaceous mudstone

2019 ◽  
Vol 1 (3) ◽  
pp. 230-240
Author(s):  
Ling Zeng ◽  
Fan Li ◽  
Jie Liu ◽  
Qianfeng Gao ◽  
Hanbing Bian
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Characteristic Curve ◽  
Initial Water Content ◽  
Test Results ◽  
Initial Water ◽  
Soil Water Characteristic Curves ◽  
Water Holding ◽  
Gravimetric Water Content ◽  
Plate Apparatus

Abstract The soil-water characteristic curve (SWCC) is often used to estimate unsaturated soil properties (e.g. strength, permeability, volume change, solute and thermal diffusivity). The SWCC of soil samples is significantly affected by cyclic wetting-drying. To examine how water content and cyclic wetting-drying affect the SWCC of disintegrated carbonaceous mudstone (DCM), SWCC tests were implemented using a pressure-plate apparatus. In addition, SWCC models for DCM considering the initial gravimetric water content and cyclic wetting-drying were developed. The test results showed that the volumetric water content (θ) of the DCM first decreased rapidly and then became stable as matric suction (s) increased. The initial water content affected the SWCC by altering the pore structure of the DCM. For a given number of wetting-drying cycles, the higher the initial water content, the higher the stabilized θ. At a given s value, θ decreased as the number of wetting-drying cycles increased, which suggests that cyclic wetting-drying reduces the water-holding capacity of DCM. The Gardner model for DCM was constructed considering initial water content and cyclic wetting-drying, and was effective at describing and predicting the SWCC model for DCM.

scholarly journals Responses of Soil Infiltration to Water Retention Characteristics, Initial Conditions, and Boundary Conditions

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 361
Author(s):  
Lesheng An ◽  
Kaihua Liao ◽  
Chun Liu
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Retention ◽  
Constant Pressure ◽  
Pressure Head ◽  
Estimation Methods ◽  
Initial Water Content ◽  
Initial Water ◽  
Cumulative Infiltration ◽  
Retention Characteristics

(1) Background: Simulation of soil water infiltration process and analysis of its influencing factors are important for water resources management. (2) Methods: In this study, the relative contributions of the soil water retention characteristics (SWRC) estimation, initial water content, and constant pressure head at upper boundary to the cumulative infiltration under various soil conditions were quantified based on the 1-D Richards’ equation and 900 scenarios. Scenario simulations were performed for two SWRC estimation methods (Jensen method and Rosetta); three different initial water contents (0.15, 0.20, and 0.25 cm3/cm3); five different constant pressure heads (0.5, 1, 2, 4, and 8 cm); and thirty soil samples with varying texture and bulk density. (3) Results: Rosetta representing the drying branch of the SWRC yielded higher simulated cumulative infiltration compared with the Jensen method representing the wetting branch of the SWRC. However, the Jensen method–predicted cumulative infiltration fluxes matched well with the measured values with a low RMSE of 0.80 cm. (4) Conclusions: The relative contribution of the SWRC estimation method to cumulative infiltration (19.1–72.2%) was compared to that of constant pressure head (14.0–65.5%), and generally greater than that of initial water content (2.2–29.9%). Findings of this study have practical significance for investigating the transport of water, nutrients, and contaminants in the unsaturated zone.

scholarly journals STUDY ON PERMEABILITY AND ELECTRICAL RESISTIVITY OF RED CLAY CONTAMINATED BY CU2+

2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Rulong Ban ◽  
Xuejun Chen ◽  
Yu Song ◽  
Pengyan Bi ◽  
Xin Yang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Electrical Resistivity ◽  
Hydraulic Conductivity ◽  
Water Content ◽  
Contaminated Soil ◽  
Initial Water Content ◽  
Red Clay ◽  
Initial Water ◽  
Electrode Method ◽  
The Relationship

In order to study the permeability characteristics of heavy metal ions contaminated red clay and explore the rapid detection of permeability of heavy metal contaminated red clay. Through variable-head permeability test and electrical resistivity test (different voltages and methods), the effects of Cu2+ concentration and initial water content on hydraulic conductivity characteristic and resistivity of contaminated red clay was systematically investigated. The relationship between permeability characteristic and electrical resistivity was further explored by taking Cu2+ concentration and moisture content as the intermediate variable. The obtained results indicate that the different voltage has no obvious effect on the resistivity of the samples. The four-phase electrode method is more accurate than the two-phase electrode method. With increasing Cu2+ concentrations the hydraulic conductivity of specimens increases, however the permeability coefficient of contaminated soil decreases with increasing initial water content. In the resistivity test, with increasing of Cu2+ concentrations and water content, the resistivity of samples presented a downward trend, which is decreased sharply at first and then tended to be gentle. The relationship between hydraulic conductivity and resistivity of contaminated soil showed a good fitting curve no matter in different Cu2+ concentration or in different water content, but the fitting curves of them presented opposite trend.

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