Compacted soils are frequently used as subgrade for pavements as well as commercial and residential buildings. The stiffness and shear strength properties of compacted soils, which are collectively denoted as Ω in this thesis, fluctuate with moisture content changes that result from the influence of environmental factors such as the evaporation and infiltration. For example, mechanistic pavement design methods require the information of resilient modulus (MR), which is the soil stiffness behavior under cyclic traffic loading, and its variation with respect to the soil moisture content determined from laboratory tests or estimation methods. Significant advances have been made during the last five decades to understand and model the variation of the Ω with respect to soil moisture content and soil suction (s) based on the principles of mechanics of unsaturated soils. There are a variety of models presently available in the literature relating the Ω to the s using different approaches. There are however uncertainties extending these models for predicting Ω - s relationships when they are used for a larger soil suction range. In addition, the good performance of these models are only valid for certain soil types for which they were developed and calibrated. Studies presented in this thesis are directed towards developing a unified methodology for modelling the relationship between the Ω and the s using limited while easy-to-obtain information. However, more emphasis has been focused on the MR - s relationships of pavement subgrade soils considering the need for the application of the mechanistic pavement design methods in Canada. The following studies have been conducted: (i) State-of-the-art review on existing equations in the literature for the MR - s relationships is summarized. A comparison study is followed to discuss the strengths and limitations of these equations; (ii) A unified methodology for modelling the Ω - s relationships is proposed. Experimental data on 25 different soils are used to verify the proposed unified methodology. The investigations are applied on small strain shear modulus, elastic modulus, and peak and critical shear strength. Good predictions are achieved for all of the investigated soils; (iii) Performance of the proposed methodology is examined for the MR - s relationships using experimental data of 11 subgrade soils. Reasonably good predictions are achieved for all of the subgrade soils; (iv) Extensive experimental investigations are conducted on the MR - s relationships for several subgrade soils collected from various regions in Canada. Experimental results suggest non-linear variation in the MR with respect to s, moisture content and the external stress. The measured results are modelled using the proposed methodology with adequate success; (v) Additional experimental investigations are performed to determine the variation of the elastic modulus (E) and unconfined compression strength (qu) with the s and the gravimetric moisture content (w) for several Canadian subgrade soils. An approach, which is developed extending the proposed unified methodology, is used to normalize the measured MR - w, E - w and qu - w relationships. It is shown that the normalized MR - w, E - w and qu - w relationships exhibit remarkable similarity and can be well described using the proposed approach. Such similarity in the normalized Ω - moisture content relationships are also corroborated using the experimental data on several other soils reported in the literature. The proposed unified methodology alleviates the need for the determination of the Ω - s relationships which requires elaborate testing equipment that needs the supervision of trained personnel and is also time-consuming and expensive. In addition, experimental programs in this thesis provide detailed experimental data on the MR, E, qu, and soil-water characteristic curves of Canadian subgrade soils. These data will be helpful for the better understanding of the hydro-mechanical behavior of the Canadian subgrade soils and for the implementation of the mechanistic pavement design method in Canada. The simple tools presented in this thesis are promising and encouraging for implementing the mechanics of unsaturated soils into conventional geotechnical engineering practice.

Temperature differences of about 5, 10, and 15 V, were applied to uniformly packed and insulated horizontal column of Millville silt loam soil using mean temperatures near 13, 14, 15, 16, 17, 18, 19, 20 and 23.5 C. The temperature distribution along the soil column was determined using copper constantan thermocouples. Soil samples were taken to determine volumetric moisture content, and soil water potential, using the vapor pressure psychometer technique. The thermodynamic flow equation of Taylor and Cary, (1964) was used to calculate the hydro-thermal transfer coefficient (β) as given by: -β=(d(μW)Τ)/dlnT where (μW)Τ is the constant temperature water potential and Τ the temperature in °K. The net transfer of moisture from the warm to the cold face of the soil column was found to depend upon the temperature difference, the mean temperature of the system, the water potential distribution that resulted and the average soil water potential as predicted by the equation. The hydro-thermal-transfer coefficient (B) was found to depend primarily on the average water potential with secondary dependence on the mean temperature. The hydro-thermal transfer coefficient was found to be small and nearly constant at high soil moisture potential where water was moving mainly in the liquid phase. At low soil water potentials the hydro-thermal transfer coefficient was again nearly constant and reached high values. In this situation water is moving mostly in the vapor phase. In the zone of water potential where significant water movement is taking place, in both liquid and vapor phases, the influence of the coefficient on the movement was not determined because of the rapidly changing relations.

The main goal of this research is to evaluate the behavior of earth pressure profiles in unsaturated soils under transient flow. In the first part, an empirical correlation is proposed to obtain the fitting parameters of Brooks and Corey’s soil-water retention model from Fredlund and Xing’s model. The retention models and the proposed equivalency between the models were assessed for 601 soil samples from the unsaturated soils hydraulic database (UNSODA). In the second part, a coupled one-dimensional hydro-mechanical model is introduced and is implemented into Rankine’s earth-pressure model to represent active and passive earth pressure profiles in unsaturated soils under transient flow. A realistic coupling process of infiltration and deformation in the porous medium is established based on the variation in permeability along with deformation in the soil body. The results showed that ignoring the hydro-mechanical coupling effect can lead to underestimation of earth pressure values, especially for fine-grained soils.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23476号 / 工博第4888号 / 新制||工||1764(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 渦岡 良介, 教授 三村 衛, 教授 肥後 陽介 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23485号 / 工博第4897号 / 新制||工||1765(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 渦岡 良介, 教授 肥後 陽介, 准教授 PIPATPONGSA Thirapong / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Levees are a significant part of the United States flood protection infrastructure. It is estimated that over 100,000 miles of levees exist in the United States. Most of these levees were designed many years ago to protect farmland and rural areas. As growth continues in the United States, many of these levees are now protecting homes and other important structures. The American Society of Civil Engineers gave the levees in the United States a grade of D- in 2009. To bring flood protection up to modern standards there requires adequate methods of evaluating levees with respect to seepage, erosion, piping and slope instability. Transient seepage analyses provide an effective method of evaluating seepage through levees and its potentially destabilizing effects. Floods against levees usually last for days or weeks. In response to a flood, pore pressures within the levee will change from negative (suction) to positive as the phreatic surface progresses through the levee. These changes can be calculated by finite element transient seepage analyses. In order for the transient seepage analysis to be valid, appropriate soil properties and initial conditions must be used. The research investigation described here provides simple and practical methods for estimating the initial conditions and soil properties required for transient seepage analyses, and illustrates their use through a number of examples. / Ph. D.

This paper presents an innovative experimental approach for simultaneous measurements of the suction head, volumetric water content, and the acoustic admittance of unsaturated sands. Samples of unsaturated sands are tested under controlled laboratory conditions. Several types of uniform sand with a wide range of particle sizes are investigated. The reported experiments are based on a standard Buchner funnel setup and a standard acoustic impedance tube. It is a novel, nondestructive, and noninvasive technique that relates the key geotechnical parameters of sands such as volumetric water content, density, and grain-size distribution to the acoustic admittance and attenuation. The results show a very sensitive dependence of the acoustic admittance on the volumetric water content controlled by the value of suction head applied. Analysis of the obtained data demonstrates that the relationship between the volumetric water content and the real part of the surface admittance in the frequency range of 400–1,200 Hz can be represented using a logarithmic equation. It is found that the coefficients in the proposed equation are directly related to the uniformity coefficient and the acoustic admittance of the dry sample, which can easily be measured or predicted for a broad range of sands. A validation exercise is conducted to examine the accuracy of the proposed equation using a sand sample with markedly different properties. The results of the validation exercise demonstrate that the proposed relations can be used to determine very accurately the volumetric water content within the porous specimen from the acoustical data. The error in the acoustically measured volumetric water content is found to be ±2.0% over the full range of volumetric water contents ( 0≤θ≤n , where n is the sample porosity).

<p> A two stage chromatographic separation method was adapted to the separation of nitrogen-containing compounds from heavy syncrude oils. Crude oil samples were first chromatographed on alumina to obtain an aliphatic fraction A1 (70 wt% of oil, <1% of total nitrogen), a polycyclic aromatic hydrocarbon fraction A2 (20%, 16%N) and a nitrogenous fraction A3 (3%, 80%N). The nitrogenous fraction was further separated on silicic acid into three fractions: a secondary-PANH fraction S1 (61% total N), an amino-PAH and tertiary-PANH fraction S2 (4%N) and a tertiary-PANH fraction S3 (9%N). One Tar Sand and two oil residue samples, provided by Shell Canada Ltd, were taken through this procedure.</p> <p> The nitrogen-containing fractions were analyzed by mass spectrometry (electron impact, methane chemical ionization and ammonia chemical ionization) and by two chromatographic methods (gas and reverse phase liquid chromatography). Further analyses were performed using gas chromatography/mass spectrometry, liquid chromatography/mass spectrometry and nuclear magnetic resonance (1H and 13C) spectroscopy.</p> <p> The nitrogenous components in the S1 fractions were shown to be alkylated carbazoles, containing from one to twenty carbons attached to the carbazole nucleus, in varying degrees of unsaturation ranging from zero to five degrees of unsaturation. The distribution of carbon substitution maximized in the C5 to C8 range for the different series of alkylcarbazoles. The distribution of the degrees of unsaturation in the Tar Sand oil sample was: saturated carbazoles, 32%, 1-degree unsaturates, 23%, 2-degree, 9%, 3-degree, 16%, 4-degree, 12% and 5-degree, 8%. In the processed Peace River residue, the ratio between the saturated, 1-, 2-, 3-, 4- and 5-degree unsaturated carbazoles was 28%:39%:18%:6%:6%:3%. From the 1H NMR spectrum the ratio of benzylic to aliphatic resonances was 1:1.25 which was interpreted to mean that the alkyl chains attached to the carbazole nucleus were short on average. A complete lack of vinyl proton absorption indicated that few alkene bonds if any were present; thus, the degrees of unsaturations must be accommodated by rings or benzo-annulations.</p> <p> Of all the analytical methods used, ammonia chemical ionization mass spectrometry (NH3 CIMS) was found to be a most useful and selective method and was used in probe MS, GC/MS and LC/MS experiments. Reverse phase liquid chromatography (RPLC) was more useful in this work than capillary column gas chromatography (CCGC). A combination of nuclear magnetic resonance (NMR) experiments (1H, 13C, 13C spectral editing, 1H-13C shift correlation and 13C T1 ) was found to be extremely useful for these samples because of the unique information these experiments provided.</p> / Thesis / Master of Science (MSc)

<p> This thesis describes an investigation into the effects of Lewis acid complexation on the photochemistry of α,β unsaturated carbonyl compounds.</p> <p> Initial studies involved the use of Nuclear Magnetic Resonance (NMR) and Ultraviolet (UV) spectroscopy in examining Lewis acid modification of the photostationary state for E/Z isomerization of various acyclic enones. The results obtained provide a good understanding of the origin of the perturbation of the photostationary state of these systems. In the course of these investigations, the question also arose as to the possible effects of complexation upon the photochemistry of cyclic enone systems where E/Z isomerization cannot occur, particularly whether this would catalyze [2+2] cycloadditions to the enone carbon/carbon double bond. Lewis acid complexed enones are widely used as activated dienophiles in Diels Alder reactions, and have been recently reported to serve as activated 'enophiles' in a photochemical dimerization of coumarin.</p> </p> The examination here is focused upon endo-tricyclo [5.2.1.02,6] deca-4,8-dien-3-one. (See Diagram in thesis). </p> <p> Reported here is a detailed investigation of the photochemistry of the AlEtCl2 complex of this compound, and the results are interpreted mechanistically. The reaction gives rise to a single product which reaches a photostationary state with the reactant complex. The isomerization is formally a [1,3] sigmatropic shift involving the isolated double bond. It seems likely however, to proceed by the formation of an allyl cation intermediate.</p> / Thesis / Master of Science (MSc)

No description available.