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Relationship between undrained shear strength and moisture content for red berea sand tailingsDu Plessis, Albertus January 2001 (has links)
A project report submitted to the Faculty of Engineering, University of the
Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the
degree of Master of Science in Engineering. / The project report deals with the relationship between the undrained shear
strength and the moisture content of Red Berea sand tailings. The tailings were
obtained from the Red Berea sand dunes near Richards Bay, Kwa-Zulu Natal,
South Africa. The geology of the area consists of Miocene deposits of red
clayey sand, classified as Berea Formation.
A method for determining stability of a tailings dam for Red Berea sand
tailings, was investigated. The general method of using the degree of saturation
of the tailings to specify the rate of rise, is not applicable to this type of tailings.
It was found that a relationship exists between the undrained shear strength of
the tailings, and the moisture content. The moisture content can easily be
measured and the undrained shear strength can then be calculated. The
calculated undrained shear strength can be used in a total stress analysis to
determine a factor of safety against failure.
This project report consists of a discussion of the literature, which was used as
the basis for the assumptions made, as well as a description of the tests
performed to prove the above-mentioned relationship. Test results are given,
interpreted and used in an illustrative example of a stability analysis. / Andrew Chakane 2020
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A model of stress distribution and cracking in cohesive soils produced by simple tillage implements /Ibarra, Sandra. January 2001 (has links)
No description available.
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Application of mechanistic approach to pavement systems permanent deformation evaluation /Guirguis, Hani Rizk January 1975 (has links)
No description available.
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The undrained behavior of saturated, dilitant siltsRose, Andrew Thomas 12 December 2008 (has links)
An extensive literature review and experimental study were performed to investigate whether cavitation and dissolved gases exiting solution from soil pore water are the cause of the erratic undrained behavior often observed in triaxial tests on saturated, dilatant silts.
The literature indicates that ground water contains various amounts of dissolved gases and that gases dissolved in soil pore water will have sufficient time to exit solution to some extent, due to the pore pressure reductions which occur during sampling and unconsolidated-undrained triaxial tests. The exit of dissolved gases from solution would increase the soil volume and affect its undrained behavior.
Experiments were performed on saturated silts to measure the pore pressure reductions which occur during sampling and unconsolidated-undrained triaxial tests. The amount of dissolved air that could come out of solution and the desaturation that a saturated soil sample could experience were also estimated.
Gas bubble formation and growth within the pores of a saturated silt could affect intergranular forces and influence the stress-strain behavior of the soil in undrained tests. Variations in the amount of dissolved gas exiting solution and forming bubbles from one specimen to another could be the cause of the erratic undrained behavior often observed for saturated silts. Bubble growth within the soil pores is believed to have lead to abrupt strain-softening in a number of the undrained tests performed in this research.
Variations in specimen disturbance may also contribute to the erratic behavior observed in undrained tests on silts. Disturbance levels and their influence on soil behavior are difficult to quantify.
Due to the unusual properties of water under negative pressure, the initial value of pore water pressure within the soil appears to have a direct influence on the undrained strength of the soil. As a result, laboratory pore water pressures should be similar to in-situ pore water pressures, in order to give reasonable undrained strength measurements. The findings of this research are believed to be worthy of further study. / Ph. D.
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Geomaterial gradation influences on interface shear behaviorFuggle, Andrew Richard 04 April 2011 (has links)
Particulate materials are ubiquitous in the natural environment and have served throughout human history as one of the basic materials for developing civilizations. In terms of human activity, the handling of particulate materials consumes approximately 10% of all the energy produced on earth. Advances in the study and understanding of particulate materials can thus be expected to have a major impact on society.
Geotechnical engineers have a long history of studying particulate materials since the fundamental building blocks of the profession include sands, silts, clays, gravels and ores, all of which are in one form or another particulates. The interface between particulates and other engineered materials is very important in determining the overall behavior of many geotechnical systems. Laboratory experimental studies into interface shear behavior has until now, been largely confined to systems involving uniformly graded sands comprised of a single particle size.
This study addresses these potential shortcomings by investigating the behavior of binary particle mixtures in contact with surfaces. The binary nature of the mixtures gives rise to a changing fabric state which in turn can affect the shear strength of the mixture. Accordingly, packing limit states and the shear strength of binary mixtures were investigated across a range of mixtures, varying in particle size ratio and the proportion of fine particles to provide a reference.
Binary mixtures in contact with smooth surfaces were investigated from both a global shear response and a contact mechanics perspective. A model was developed that allowed for the prediction of an interface friction coefficient based on fundamental material properties, particle and mixture parameters. Surface roughness changes as a result of shearing were also examined.
The interface shear behavior with rough interfaces was examined in the context of the relative roughness between particles and surface features. The interpretation of traditional measures of relative roughness suffer from the need for a definitive average particle size, which is ambiguous in the case of non-uniform mixtures. Measures of an applicable average particle size for binary mixtures were evaluated.
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Use of the cone penetration test to assess the liquefaction potential of tailings storage facilitiesTorres Cruz, Luis Alberto January 2016 (has links)
A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy, 2016 / The performance in tailings storage facilities (TSFs) of three methods based on the cone penetration test (CPT) to assess liquefaction potential is explored. For two of these methods the investigation highlights potential limitations mostly related with the experimental data that supports some of the equations used by the methods. However, the methodologies yielded mostly correct performance predictions when implemented on TSF case histories in which an undrained response is believed to have occurred. The positive performance of both methodologies must be tempered by the limitations identified in the methods.
The steady state line (SSL) is an input of the third method considered. Accordingly, the correlation between the SSL and soil index parameters was investigated using a database of 151 non-plastic soiltypes compiled from data previously reported in the literature. The SSLs were modelled in void ratio (e) - mean effective stress (p') space, using a logarithmic equation. The y-intercept of the SSL is termed Γ, and the slope is termed λ. A direct, and linear (R2 = 0.74) correlation between the minimum void ratio (emin) and Γ was found. Although previous research has explored the effect of non-plastic fines on the SSL, the analysis presented herein shows that the Γ-emin correlation is independent of fines content. The correlation is also independent of the angularity of the particles provided that these are bulky, as opposed to platy. A direct λ-emin correlation was also found; however this correlation is much weaker and probably obscured by uncertainties in void ratio measurements.
Triaxial testing was conducted to determine the SSLs of three tailings soiltypes obtained from a single TSF. The trends observed in the resulting SSLs are in agreement with the Γ-emin and λ-emin correlations from the database.
An assessment was made of the sensitivity of the third method, which is based on a state parameter (ψ), to variations in λ throughout a single TSF. It was found that in some TSFs, the variations of λ are small enough to be disregarded without significantly affecting the accuracy of ψ. However, in other TSFs it is necessary to estimate how λ varies throughout the deposit.
iii / CK2017
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Stress-strain-strength anisotropy of varved clays.Sambhandharaksa, Surachat January 1977 (has links)
Thesis. 1977. Sc.D.--Massachusetts Institute of Technology. Dept. of Civil Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Bibliography: leaves 381-386. / Sc.D.
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Cone penetration in clays.Vivatrat, Vitoon January 1978 (has links)
Thesis. 1978. Sc.D.--Massachusetts Institute of Technology. Dept. of Civil Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 416-426. / Sc.D.
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Considerations of soil remoulding and application to sensitivityTang, King Yan. January 1980 (has links)
No description available.
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Applications of cone, vane and vane-cone to predict stress-strain behaviour of unsaturated cohesive soilLiao, Chung-Lon January 1986 (has links)
No description available.
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