An Appraisal of Soil Index Tests

1986 ◽  
Vol 2 (1) ◽  
pp. 317-323 ◽  
Author(s):  
F. Medhat ◽  
I. L. Whyte
Keyword(s):  
Shear Strength ◽  
Liquid Limit ◽  
Clay Soils ◽  
Alternative Procedure ◽  
Rational Basis ◽  
Plastic Limit ◽  
Fine Soil ◽  
Index Tests ◽  
Bead Method ◽  
Adequate Reliability

AbstractThe development of liquid and plastic limit tests is reviewed. It is confirmed that the fall cone method is more reliable and reproducible than the Casagrande method for the liquid limit, and this test is adequate for index purposes. The plastic limit has remained effectively unchanged for sixty years and there is no accepted alternative procedure. The Atterberg/Terzaghi rolling bead method is not of adequate reliability and reproducibility. It is proposed that the remoulded shear strength of a fine soil provides a rational basis for index tests. Extrusion and cones have been used to investigate simple methods and it is concluded that both approaches have potential, with the cone test probably being the simpler and more economical approach. Four clay soils were used in the investigation, and it is recommended that a wider range of plastic soils be tested to confirm or otherwise the validity of this approach to index testing.

scholarly journals Prediction of Shear Strength of Soil Using Direct Shear Test and Support Vector Machine Model

2020 ◽  
Vol 14 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Hai-Bang Ly ◽  
Binh Thai Pham
Keyword(s):  
Support Vector Machine ◽  
Shear Strength ◽  
Moisture Content ◽  
Mean Squared Error ◽  
Learning Algorithm ◽  
Liquid Limit ◽  
Support Vector ◽  
Plastic Limit ◽  
Svm Model ◽  
Soil Shear Strength

Background: Shear strength of soil, the magnitude of shear stress that a soil can maintain, is an important factor in geotechnical engineering. Objective: The main objective of this study is dedicated to the development of a machine learning algorithm, namely Support Vector Machine (SVM) to predict the shear strength of soil based on 6 input variables such as clay content, moisture content, specific gravity, void ratio, liquid limit and plastic limit. Methods: An important number of experimental measurements, including more than 500 samples was gathered from the Long Phu 1 power plant project’s technical reports. The accuracy of the proposed SVM was evaluated using statistical indicators such as the coefficient of correlation (R), Root Mean Squared Error (RMSE), Mean Absolute Error (MAE) over a number of 200 simulations taking into account the random sampling effect. Finally, the most accurate SVM model was used to interpret the prediction results due to Partial Dependence Plots (PDP). Results: Validation results showed that SVM model performed well for prediction of soil shear strength (R = 0.9 to 0.95), and the moisture content, liquid limit and plastic limit were found as the three most affecting features to the prediction of soil shear strength. Conclusion: This study might help in quick and accurate prediction of soil shear strength for practical purposes in civil engineering.

Shear strength of remolded soils at consistency limits

2010 ◽  
Vol 47 (3) ◽  
pp. 259-266 ◽  
Author(s):  
Kamil Kayabali ◽  
Osman Oguz Tufenkci
Keyword(s):  
Shear Strength ◽  
Linear Relationship ◽  
Water Content ◽  
Undrained Shear Strength ◽  
Liquid Limit ◽  
Soil Samples ◽  
Atterberg Limits ◽  
Plastic Limit ◽  
Water Contents ◽  
Undrained Shear

The undrained shear strength of remolded soils is of concern in certain geotechnical engineering applications. Several methods for determining this parameter exist, including the laboratory vane test. This study proposes a new method to estimate the undrained shear strength, particularly at the plastic and liquid limits. For 30 inorganic soil samples of different plasticity levels, we determined the Atterberg limits, then performed a series of reverse extrusion tests at different water contents. The plastic and liquid limits are derived from the linear relationship between the logarithm of the extrusion pressure and water content. The tests show that the average undrained shear strength determined from the extrusion pressures at the plastic limit is about 180 kPa, whereas the average undrained shear strength at the liquid limit is 2.3 kPa. We show that the undrained shear strength of remolded soils at any water content can be estimated from the Atterberg limits alone. Although the laboratory vane test provides a reasonable undrained shear strength value at the plastic limit, it overestimates the undrained shear strength at the liquid limit and thus, care must be taken when the laboratory vane test is used to determine undrained shear strengths at water contents near the liquid limit.

scholarly journals Plasticity, Swell-Shrink, and Microstructure of Phosphogypsum Admixed Lime Stabilized Expansive Soil

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Jijo James ◽  
P. Kasinatha Pandian
Keyword(s):  
Industrial Waste ◽  
Expansive Soil ◽  
Liquid Limit ◽  
Unconfined Compression ◽  
Plastic Limit ◽  
Unconfined Compression Test ◽  
Microstructural Study ◽  
Stabilized Soil ◽  
Free Swell ◽  
Index Tests

The study involved utilization of an industrial waste, Phosphogypsum (PG), as an additive to lime stabilization of an expansive soil. Three lime dosages, namely, initial consumption of lime (ICL), optimum lime content (OLC), and less than ICL (LICL), were identified for the soil under study for stabilizing the soil. Along with lime, varying doses of PG were added to the soil for stabilization. The effect of stabilization was studied by performing index tests, namely, liquid limit, plastic limit, shrinkage limit, and free swell test, on pulverized remains of failed unconfined compression test specimens. The samples were also subjected to a microstructural study by means of scanning electron microscope. Addition of PG to lime resulted in improvement in the plasticity and swell-shrink characteristics. The microstructural study revealed the formation of a dense compact mass of stabilized soil.

scholarly journals Prediction of Shear Strength of Soil Using Direct Shear Test and Support Vector Machine Model

2020 ◽  
Vol 14 (1) ◽  
pp. 268-277 ◽  
Author(s):  
Hai-Bang Ly ◽  
Binh Thai Pham
Keyword(s):  
Support Vector Machine ◽  
Shear Strength ◽  
Moisture Content ◽  
Mean Squared Error ◽  
Learning Algorithm ◽  
Liquid Limit ◽  
Support Vector ◽  
Plastic Limit ◽  
Svm Model ◽  
Soil Shear Strength

Background: Shear strength of soil, the magnitude of shear stress that a soil can maintain, is an important factor in geotechnical engineering. Objective: The main objective of this study is dedicated to the development of a machine learning algorithm, namely Support Vector Machine (SVM) to predict the shear strength of soil based on 6 input variables such as clay content, moisture content, specific gravity, void ratio, liquid limit and plastic limit. Methods: An important number of experimental measurements, including more than 500 samples was gathered from the Long Phu 1 power plant project’s technical reports. The accuracy of the proposed SVM was evaluated using statistical indicators such as the coefficient of correlation (R), Root Mean Squared Error (RMSE), Mean Absolute Error (MAE) over a number of 200 simulations taking into account the random sampling effect. Finally, the most accurate SVM model was used to interpret the prediction results due to Partial Dependence Plots (PDP). Results: Validation results showed that SVM model performed well for prediction of soil shear strength (R = 0.9 to 0.95), and the moisture content, liquid limit and plastic limit were found as the three most affecting features to the prediction of soil shear strength. Conclusion: This study might help in quick and accurate prediction of soil shear strength for practical purposes in civil engineering.

scholarly journals The undrained strength – liquidity index relationship

2014 ◽  
Vol 51 (9) ◽  
pp. 1073-1086 ◽  
Author(s):  
P.J. Vardanega ◽  
S.K. Haigh
Keyword(s):  
Shear Strength ◽  
Undrained Shear Strength ◽  
Liquid Limit ◽  
Mathematical Function ◽  
Plastic Limit ◽  
Mathematical Relationship ◽  
Liquidity Index ◽  
Undrained Strength ◽  
Statistical Improvement ◽  
Undrained Shear

A database of 641 fall cone tests on 101 soil samples from 12 countries has been analysed to determine the best mathematical relationship linking undrained shear strength with liquidity index. From the database, it is shown that the use of a linear relationship linking liquidity index and the logarithm of undrained shear strength that uses the commonly assumed 100-fold factor increase in strength from the liquid to plastic limit overpredicts the measured data of soil strength. The use of a factor of about 35 for the ratio between the strength at liquid limit and that extrapolated to the plastic limit is shown to be more realistic. Logarithmic liquidity index is examined and found to also correlate strongly with the logarithm of undrained shear strength; however, it is shown that no great statistical improvement is present compared with the semi-logarithmic formulation. When considering data of individual soils a power law fitting is statistically shown to be the preferred mathematical function.

scholarly journals Influence of wood-derived biochar on the compactibility and strength of silt loam soil

2017 ◽  
Vol 31 (2) ◽  
pp. 149-155 ◽  
Author(s):  
Ahmed Ahmed ◽  
Yvan Gariepy ◽  
Vijaya Raghavan
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Bulk Density ◽  
Penetration Resistance ◽  
Liquid Limit ◽  
Optimum Moisture Content ◽  
Silt Loam ◽  
Plastic Limit ◽  
Density Maximum ◽  
Loam Soil

Abstract Biochar is proven to enhance soil fertility and increase crop productivity. Given that the influence of biochar on soil compaction remains unclear, selected physico-mechanical properties of soil amended with wood-derived biochar were assessed. For unamended silt loam, the bulk density, maximum bulk density, optimum moisture content, plastic limit, liquid limit, and plasticity index were 1.05 Mg m-3, 1.69 Mg m-3, 16.55, 17.1, 29.3, and 12.2%, respectively. The penetration resistance and shear strength of the unamended silt loam compacted in the standard compaction Proctor mold and at its optimum moisture content were 1800 kPa and 850 kPa, respectively. Results from amending the silt loam with 10% particle size ranges (0.5-212 μm) led to relative decreases of 18.1, 17.75, 66.66, and 97.4% in bulk density, maximum bulk density, penetration resistance, and shear strength, respectively; a 26.8% relative increase in optimum moisture content; along with absolute increases in plastic limit, liquid limit, and plasticity index of 5.3, 13.7, and 8.4%, respectively. While the biochar-amended silt loam soil was more susceptible to compaction, however, soil mechanical impedance enhanced.

scholarly journals Correlations for undrained shear strength of Finnish soft clays

2016 ◽  
Vol 53 (10) ◽  
pp. 1628-1645 ◽  
Author(s):  
Marco D’Ignazio ◽  
Kok-Kwang Phoon ◽  
Siew Ann Tan ◽  
Tim Tapani Länsivaara
Keyword(s):  
Shear Strength ◽  
Undrained Shear Strength ◽  
Liquid Limit ◽  
Regression Analyses ◽  
Plastic Limit ◽  
Soft Clays ◽  
Natural Water Content ◽  
Vertical Effective Stress ◽  
First Time ◽  
Undrained Shear

The study focuses on the derivation of transformation models for undrained shear strength (su) of Finnish soft sensitive clays. Specific correlation equations for su of Finnish clays are presented in this work for the first time. Field and laboratory measurements from 24 test sites in Finland are exploited for this purpose and a multivariate database is constructed. The multivariate data consist of su from the field vane test, preconsolidation stress, vertical effective stress, liquid limit, plastic limit, natural water content, and sensitivity. The main objective is to evaluate the interdependence of su, consolidation stresses, and index parameters and provide a consistent framework for practical use. The new correlations are established through regression analyses. The constructed framework is further validated by another independent multivariate database of clays from Sweden and Norway as well as by empirical equations for Swedish and Norwegian clays. Existing correlations are evaluated for Finnish and Scandinavian clays. Finally, bias and uncertainties of the new correlations are presented.

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