ANALYSIS OF EMPIRICAL COMPRESSION INDEX EQUATIONS USING THE WATER CONTENT

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Amir W. Al-Khafaji ◽  
Krishnanand Y. Maillacheruvu ◽  
Melissa Hoerber
Keyword(s):  
Water Content ◽  
Empirical Models ◽  
Soil Types ◽  
Data Sets ◽  
Regression Equations ◽  
Compression Index ◽  
Empirical Formulas ◽  
Wide Range ◽  
Compression Data ◽  
Water Contents

This paper proposes a new method to evaluate the reliability of published empirical formulas in terms of accuracy and applicability to different soil types. Different empirical models are proposed to properly approximate the compression index for a wide range of water contents and soil types. They were developed using a unique technique and a substantial number of published regression equations and compression data. Familiar empirical equations were examined for their reliability in predicting the compression index of clay for any water content. A comparison was made between available and newly-proposed empirical formulas using combined regression data sets compiled independently by several authors. The newly proposed empirical compression index equations are applicable to a wide range of clay soils, and in validating other published relationships. The degree of scatter and variations in the computed compression index values are minimized for any water content.

ANALYSIS OF EMPIRICAL COMPRESSION INDEX EQUATIONS USING THE LIQUID LIMIT

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Amir W. Al-Khafaji ◽  
Krishnanand Y. Maillacheruvu ◽  
Matthew Sainz ◽  
Rebecca Neuman
Keyword(s):  
Soil Property ◽  
Liquid Limit ◽  
Empirical Models ◽  
Soil Types ◽  
Data Sets ◽  
Regression Equations ◽  
Compression Index ◽  
Empirical Formulas ◽  
Wide Range ◽  
Compression Data

This paper proposes a new method to evaluate the reliability of published empirical formulas in terms of accuracy and applicability to different soil types. Different empirical models are proposed to properly approximate the compression index for a wide range of liquid limits and soil types. They were developed using a unique Soil Property Line (SPL) developed using a substantial number of published regression equations and compression data. Familiar empirical equations were examined for their reliability in predicting the compression index of clay for any liquid limit. A comparison was made between available and newly-proposed empirical formulas using combined regression data sets compiled independently by several authors. The newly proposed empirical compression index equations are applicable to wide ranges of clay soils, validating other published relationships. The degree of scatter and variations in the computed compression index values are minimized for any liquid limit.

ANALYSIS OF EMPIRICAL COMPRESSION INDEX EQUATIONS USING THE VOID RATIO

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Amir Al-Khafaji ◽  
Krishnanand Maillacheruvu ◽  
Robert Jacobs
Keyword(s):  
Void Ratio ◽  
New Technique ◽  
Soil Types ◽  
Regression Equations ◽  
Compression Index ◽  
Data Set ◽  
Data Points ◽  
Compression Data ◽  
A New Technique ◽  
Selection Of

A new technique to assess the reliability of published compression index equations in terms of soil void ratio is presented. Several published equations pertaining to different soil types are examined in terms of accuracy and applicability. The new technique employs regression analysis to examine a substantial number of published compression data objectively. The traditional bias inherent in the selection of the number of data points and the range of void ratios for a given regression equation is eliminated. This was made possible by creating ranges for the compression index irrespective of the data set involved. This technique revealed that a strong correlation exists between the slopes and intercepts of all published equations. The slopes and intercepts of the newly developed regression equations were used to compare several well know published equations to assess accuracy and applicability. The proposed technique permits the examination of the authenticity of any published empirical equations relating to the compression index of clay to void ratio.

The undrained strength of some thawed permafrost soils

1979 ◽  
Vol 16 (2) ◽  
pp. 420-427
Author(s):  
John F. Nixon ◽  
Alan J. Hanna
Keyword(s):  
Undrained Shear Strength ◽  
Soil Types ◽  
Density Range ◽  
Mackenzie Delta ◽  
Sample Depth ◽  
Wide Range ◽  
Permafrost Soils ◽  
Undrained Strength ◽  
Water Contents ◽  
Undrained Shear

A large number of undrained shear strengths have been measured for thawed, undrained permafrost samples obtained from the Niglintgak Peninsula area of the Mackenzie Delta, N.W.T. The samples are mostly deltaic silts, with a few clay tills, and cover a wide range of depths, water contents, and frozen density. The undrained shear strengths of the thawed samples have been correlated with water content, frozen density, and sample depth. For these soil types, the strength is shown to decrease to zero at frozen densities of less than about 1670 kg/m3 and at water contents greater than about 35–42%. In the Niglintgak area, the undrained shear strength of the thawed samples below a depth of 10 m becomes relatively constant in the range of 23–43 kPa. This corresponds to a frozen density range of 1780–1870 kg/m3, and previous experience with soils of this nature indicates that the corresponding thaw settlement at these depths would be less than 10%.

Effects of water content and temperature on the surface conductivity of bentonite clay

Soil Research ◽  
2012 ◽  
Vol 50 (1) ◽  
pp. 44 ◽  
Author(s):  
M. A. Mojid ◽  
H. Cho
Keyword(s):  
Water Content ◽  
Bentonite Clay ◽  
Ionic Mobility ◽  
Surface Conductivity ◽  
Temperature Correction ◽  
Hydration Layer ◽  
Temperature Range ◽  
Wide Range ◽  
Hydration Layers ◽  
Water Contents

This study explored the effects of water content and temperature on the mobility of exchangeable cations (termed the surface ionic mobility and hereafter ionic mobility) in the hydration layers of bentonite clay. The ionic mobility directly governs the surface conductivity of the clay. The investigation was done by measuring the bulk electrical conductivity (EC) of four sand–bentonite mixtures of different proportions for a wide range of water contents under constant temperature, and three bentonite samples at different water contents over 5–90°C. The ionic mobility was determined from the surface conductivity at the mean ionic strength of the hydration layers. The ionic mobility in the sand–bentonite samples increased with an increase in hydration layer thickness. For a given thickness of the hydration layer, the greater the bentonite content of a sample, the smaller was the ionic mobility. The ionic mobility in the bentonite samples at different water contents also increased, at reduced rates, with a rise in temperature. Consequently, the surface conductivity of the samples increased non-uniformly, at two different rates, with an increase in temperature. The increasing rate of this conductivity depended on temperature; over the low temperature range which depended on the water content, the rate was 0.013 dS/m.K, and over higher temperature range, the rate decreased to 0.008 dS/m.K. The commonly used temperature correction factor, 0.019 dS/m.K, for EC therefore did not hold true for the bentonite samples.

WATER TOLERANCE OF MIXTURES OF GASOLINE WITH ETHYL ALCOHOL, ISOPROPYL ALCOHOL AND BENZENE

1934 ◽  
Vol 11 (4) ◽  
pp. 505-519
Author(s):  
Colin H. Bayley ◽  
Clarence Yardley Hopkins
Keyword(s):  
Water Content ◽  
Ethyl Alcohol ◽  
Isopropyl Alcohol ◽  
The Other ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Water Tolerance ◽  
Wide Range ◽  
Critical Water Content ◽  
Water Contents

The relation between water content and critical solution temperature of mixtures of gasoline with ethanol and isopropanol and with ethanol and benzene has been determined. Curves are presented which show the critical water contents of a wide range of mixtures at any temperature between + 20° and − 50 °C. Three gasolines were used, two being straight-run and one a cracked gasoline. The mixtures contained 60 to 90% of gasoline with varying proportions of the other two components. Isopropanol has been found to bring about a marked increase in the critical water content of gasoline-ethanol mixtures to which it is added. Benzene is shown to be of little value for this purpose within the range of mixtures studied.

Soil water changes under fallow-crop treatments in relation to soil type, rainfall and yield of wheat

1971 ◽  
Vol 11 (49) ◽  
pp. 236 ◽  
Author(s):  
JE Schultz
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Storage ◽  
South Australia ◽  
Soil Types ◽  
Soil Water Storage ◽  
Fallow Period ◽  
One Year ◽  
Water Contents ◽  
Soil Water Contents

Soil water changes under fallow (initial cultivation in spring), grassland (initial cultivation in autumn) and the succeeding wheat crops were recorded at two to three weekly intervals in three consecutive seasons in three soil types representing the range of wheat-growing soils in South Australia. Differences in water content between the two treatments developed soon after the start of fallowing due to the greater loss of water from grassland in spring. Rainfall during the fallow period contributed little to soil water storage except in one year when heavy spring rains were recorded. In some instances the water content in the fallowed soils at seeding was less than at the start of fallowing, but the fallowed soils consistently retained more water than the grassland soils. Soil water contents decreased after August of the crop year (end of tillering) and by harvest the wheat crops had commonly dried the soil to a depth of 150 cm. Fallow crops used more water and produced significantly higher wheat yields with a greater efficiency of water use in all trials.

Soil properties influencing compactability of forest soils in British Columbia

2004 ◽  
Vol 84 (2) ◽  
pp. 219-226 ◽  
Author(s):  
M. Krzic ◽  
C. E. Bulmer ◽  
F. Teste ◽  
L. Dampier ◽  
S. Rahman
Keyword(s):  
British Columbia ◽  
Organic Matter ◽  
Water Content ◽  
Bulk Density ◽  
Forest Soils ◽  
Tree Planting ◽  
Total Carbon ◽  
Regression Equations ◽  
Wide Range ◽  
Proctor Test

The widespread use of heavy machinery during harvesting and site preparation in timber plantations in British Columbia (BC) has led to concerns that compaction causes a reduction in long-term soil productivity. Impacts of properties such as total C, water content, and texture on compactability of forest soils in BC were assessed. Two compactability indices were used: maximum bulk density (MBD) and susceptibility to compaction (SC) determined by the standard Proctor test. Soil samples were collected from 16 sites throughout BC covering a wide range of biogeoclimatic zones. Soils varied in texture (12 to 87% sand, 9 to 76% silt, and 2 to 53% clay) and organic matter content (18 to 76 g kg-1 total C). A strong negative correlation was observed between MBD and gravimetric water content at which MBD was achieved (WMBD) and between MBD and total C. Similarly, WMBD and total C had strong effects on SC. The estimation of either MBD or SC values was not substantially improved by including texture parameters to the regression equations in addition to the total C. The implication of the relationships observed in this study is that increases in soil organic matter reduce the risk of compactability, which is particularly important for forest soils where compaction is generally not corrected by implements after tree planting. The information is also useful for assessing the extent of compaction on soils affected by machine traffic. Key words: Soil compaction, Susceptibility to compaction, maximum bulk density, Proctor test, total carbon

scholarly journals Comparison of Two Methods for Total Inorganic Carbon Estimation in Three Soil Types in Mediterranean Area

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 409
Author(s):  
Rita Leogrande ◽  
Carolina Vitti ◽  
Mirko Castellini ◽  
Marcello Mastrangelo ◽  
Francisco Pedrero ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Quantitative Estimation ◽  
Mediterranean Area ◽  
Soil Types ◽  
Carbonate Content ◽  
Regression Equations ◽  
Total Inorganic Carbon ◽  
Data Set ◽  
Wide Range ◽  
Dry Combustion

The objective of this study was to compare the results of calcimetric and dry combustion methods for quantitative estimation of soil total inorganic carbon (TIC). To this aim, 117 soil samples from three localities in the Mediterranean area (one in Spain and two in Southern Italy), representing a wide range of total inorganic carbon contents (ranging from 1.9 to 54 g 100g−1), were collected. TIC (expressed as CaCO3) was quantified using the volumetric calcimeter method, as reference, and dry combustion in order to find an accurate and rapid method, suitable for different types of soils. The results revealed a concordance between the two methods compared, as shown by the recovery values close to one, for the whole data set and for data grouped per experimental site. Specifically, the dry combustion method showed slightly greater values of TIC compared to volumetric method, probably due to soil acid pretreatments, in dry combustion, and to an incomplete decomposition of carbonates that would require more time for removal, in a calcimeter method. Linear regression equations between the two methods were not affected by different soil types. Overall, our study demonstrated that the dry combustion was a reliable method and could provide accurate estimates of TIC in soils with different calcium carbonate content.

Seed mass variation potentially masks a single critical water content in recalcitrant seeds

2004 ◽  
Vol 14 (2) ◽  
pp. 185-195 ◽  
Author(s):  
Matthew I. Daws ◽  
Christiane S. Gaméné ◽  
Sheila M. Glidewell ◽  
Hugh W. Pritchard
Keyword(s):  
Water Content ◽  
Seed Mass ◽  
Tropical Tree ◽  
Recalcitrant Seeds ◽  
Seed Population ◽  
Wide Range ◽  
Critical Water Content ◽  
Whole Seed ◽  
Water Contents ◽  
Seed Water Content

For recalcitrant seeds, mortality curves of germination versus water content typically imply a wide range of desiccation sensitivities within a seed population. However, seed to seed differences in water content, during desiccation, may confound our interpretation of these mortality plots. Here, we illustrate this problem for two batches ofVitellaria paradoxa(Sapotaceae) seeds collected in 1996 and 2002. Whole seeds were desiccated to various target water contents (TWCs) using silica gel. During desiccation, smaller seeds in the population dried most rapidly. Consequently, there was a significant linear relationship between whole-seed water content and seed mass during the drying process. In addition, following desiccation to low TWCs, only the largest seeds in the population retained viability. Taken together, this suggests that the larger seeds survived, not as a consequence of great relative desiccation tolerance, but as a result of taking longer to desiccate. Subsequently, the critical water content (CWC) for viability loss was calculated, based on the assumptions that in the seed population whole-seed water content during desiccation was normally distributed and the smallest, and hence driest, seeds were killed first. Using this approach, the driest seeds in the population that were killed, at each TWC, were always below a single CWC (c. 20% and 26% in 1996 and 2002, respectively). In subsequent experiments the effect of seed size variation on the response to desiccation was confirmed by conducting desiccation screens on seeds sorted into two discrete size classes, i.e. the seed-lot heterogeneity in mass was reduced. Using this approach, the mortality curves had a steeper slope. Furthermore, data for 24 tropical tree species from the Database of Tropical Tree Seed Research (DABATTS) revealed that seed lots with less variability in mass had steeper mortality curves. Thus, taken together, the data suggest that, at least for whole seeds, the wide range of desiccation sensitivities typically inferred is an artefact of seed to seed variation in mass, and hence water contents, during drying.

scholarly journals Influence of Loosely Bound Water on Compressibility of Compacted Fine-Grained Soils

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Rui Zhang ◽  
Mengli Wu ◽  
Prince Kumar ◽  
Qian-Feng Gao
Keyword(s):  
Water Content ◽  
Solid Phase ◽  
Bound Water ◽  
Xrd Analysis ◽  
Coarse Grained ◽  
Compression Index ◽  
X Ray Diffraction ◽  
Fine Grained ◽  
Previous Assumption ◽  
Water Contents

This study aimed to investigate the influence of loosely bound water (LBW) on the compressibility of compacted fine-grained soils and accurately determine the soil’s compression index. Four fine-grained soils (i.e., heavy clay, heavy silt, lean clay, and lean silt) and a coarse-grained soil were examined. The volumetric flask method was used to measure the LBW contents of the five soils. X-ray diffraction (XRD) analysis was then performed to test the mineral compositions and help explain the reason why the LBW content varied between different soils. A concept of modified void ratio was proposed by assuming that LBW is a part of the solid phase in soil. Subsequently, consolidation tests and permeability tests were conducted on saturated compacted specimens. The results show that the compression indexes or permeability coefficients tend to be the same for the soils with identical initial modified void ratios. Consolidation tests were also carried out on the unsaturated compacted heavy silt of four different dry densities prepared at a water content higher than the optimum. They show that the compression of unsaturated soil occurs if pore air is discharged when the water content is less than the LBW content. This confirms the previous assumption that LBW can be regarded as a part of the soil solid phase. A modified compression index was deduced and implemented to predict the settlement of a road embankment. The result suggests that the modified compression index is capable of calculating the compression of fine-grained soils, whose water contents are higher than their LBW contents.

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