Matching Items (5)
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- All Subjects: Geotechnical Engineering
- Creators: Kavazanjian, Edward
Description
This thesis presents a probabilistic evaluation of multiple laterally loaded drilled pier foundation design approaches using extensive data from a geotechnical investigation for a high voltage electric transmission line. A series of Monte Carlo simulations provide insight about the computed level of reliability considering site standard penetration test blow count value variability alone (i.e., assuming all other aspects of the design problem do not contribute error or bias). Evaluated methods include Eurocode 7 Geotechnical Design procedures, the Federal Highway Administration drilled shaft LRFD design method, the Electric Power Research Institute transmission foundation design procedure and a site specific variability based approach previously suggested by the author of this thesis and others. The analysis method is defined by three phases: a) Evaluate the spatial variability of an existing subsurface database. b) Derive theoretical foundation designs from the database in accordance with the various design methods identified. c) Conduct Monti Carlo Simulations to compute the reliability of the theoretical foundation designs. Over several decades, reliability-based foundation design (RBD) methods have been developed and implemented to varying degrees for buildings, bridges, electric systems and other structures. In recent years, an effort has been made by researchers, professional societies and other standard-developing organizations to publish design guidelines, manuals and standards concerning RBD for foundations. Most of these approaches rely on statistical methods for quantifying load and resistance probability distribution functions with defined reliability levels. However, each varies with regard to the influence of site-specific variability on resistance. An examination of the influence of site-specific variability is required to provide direction for incorporating the concept into practical RBD design methods. Recent surveys of transmission line engineers by the Electric Power Research Institute (EPRI) demonstrate RBD methods for the design of transmission line foundations have not been widely adopted. In the absence of a unifying design document with established reliability goals, transmission line foundations have historically performed very well, with relatively few failures. However, such a track record with no set reliability goals suggests, at least in some cases, a financial premium has likely been paid.
ContributorsHeim, Zackary (Author) / Houston, Sandra (Thesis advisor) / Witczak, Matthew (Committee member) / Kavazanjian, Edward (Committee member) / Zapata, Claudia (Committee member) / Arizona State University (Publisher)
Created2014
Description
This thesis describes the conduct and interpretation of large scale direct shear testing of municipal solid waste (MSW) which was recently conducted at Arizona State University under the guidance of Dr. Edward Kavazanjian Jr. This research was performed to establish the shear strength parameters for MSW of a particular landfill in the eastern United States. As part of this research, the unit weight of the material of interest was recorded to help establish if the properties of the waste tested in this project were consistent with the properties of MSW reported in the technical literature.
The paper begins with an overview of scholarly articles on shear strength and unit weight of MSW. This overview summarizes trends found in other MSW investigations. The findings described in these articles served as a basis to determine if the direct shear test results in this investigation complied with typical values reported in other MSW investigations.
A majority of this thesis is dedicated to describing testing protocol, nuances of experimental execution, and test results of the direct shear tests. This culminates in an analysis of the shear strength parameters and consolidated unit weight exhibited by the MSW tested herein. Throughout the testing displacement range of 3.5 inches, none of the MSW specimens achieved a peak shear stress. Consequently, the test results were analyzed at displacements of 1.7 inches, 2.1 inches, and 2.4 inches during the tests to develop Mohr-Coulomb envelopes for each specified displacement. All three envelopes indicated that the cohesion of the material was effectively 0 psf). The interpreted angles of internal friction were of 30.6°, 33.7°, and 36.0° for the displacements of 1.7, 2.1, and 2.4 inches, respectively. These values correlate well with values from previous investigations, indicating that from a shear strength basis the waste tested in this project was typical of MSW from other landfills. Analysis of the consolidated unit weight of the MSW specimens also suggests the MSW was similar to in-situ MSW which was placed in a landfill with low levels of compaction and small amounts of cover soil.
The paper begins with an overview of scholarly articles on shear strength and unit weight of MSW. This overview summarizes trends found in other MSW investigations. The findings described in these articles served as a basis to determine if the direct shear test results in this investigation complied with typical values reported in other MSW investigations.
A majority of this thesis is dedicated to describing testing protocol, nuances of experimental execution, and test results of the direct shear tests. This culminates in an analysis of the shear strength parameters and consolidated unit weight exhibited by the MSW tested herein. Throughout the testing displacement range of 3.5 inches, none of the MSW specimens achieved a peak shear stress. Consequently, the test results were analyzed at displacements of 1.7 inches, 2.1 inches, and 2.4 inches during the tests to develop Mohr-Coulomb envelopes for each specified displacement. All three envelopes indicated that the cohesion of the material was effectively 0 psf). The interpreted angles of internal friction were of 30.6°, 33.7°, and 36.0° for the displacements of 1.7, 2.1, and 2.4 inches, respectively. These values correlate well with values from previous investigations, indicating that from a shear strength basis the waste tested in this project was typical of MSW from other landfills. Analysis of the consolidated unit weight of the MSW specimens also suggests the MSW was similar to in-situ MSW which was placed in a landfill with low levels of compaction and small amounts of cover soil.
ContributorsCuret, Dylan Shea (Author) / Kavazanjian, Edward (Thesis director) / Houston, Sandra (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Nanotechnology has been applied to many areas such as medicine, manufacturing, catalysis, food, cosmetics, and energy since the beginning 21st century. However, the application of nanotechnology to geotechnical engineering has not received much attention. This research explored the technical benefits and the feasibility of applying nanoparticles in geotechnical engineering. Specific studies were conducted by utilizing high-pressure devices, axisymmetric drop shape analysis (ADSA), microfluidics, time-lapse technology, Atomic Force Microscopy (AFM) to develop experiments. The effects of nanoparticle on modifying interfacial tension, wettability, viscosity, sweep efficiency and surface attraction forces were investigated. The results show that nanoparticles mixed in water can significantly reduce the interfacial tension of water in CO2 in the applications of nanofluid-CO2 flow in sediments; nanoparticle stabilized foam can be applied to isolate contaminants from clean soils in groundwater/soil remediation, as well as in CO2 geological sequestration or enhanced oil/gas recovery to dramatically improve the sweep efficiency; nanoparticle coatings are capable to increase the surface adhesion force so as to capture migrating fine particles to help prevent clogging near wellbore or in granular filter in the applications of oil and gas recovery, geological CO2 sequestration, geothermal recovery, contaminant transport, groundwater flow, and stormwater management system.
ContributorsZheng, Xianglei (Author) / Jang, Jaewon (Thesis advisor) / Zapata, Claudia (Committee member) / Kavazanjian, Edward (Committee member) / Arizona State University (Publisher)
Created2016
Description
Currently conventional Subtitle D landfills are the primary means of disposing of our waste in the United States. While this method of waste disposal aims at protecting the environment, it does so through the use of liners and caps that effectively freeze the breakdown of waste. Because this method can keep landfills active, and thus a potential groundwater threat for over a hundred years, I take an in depth look at the ability of bioreactor landfills to quickly stabilize waste. In the thesis I detail the current state of bioreactor landfill technologies, assessing the pros and cons of anaerobic and aerobic bioreactor technologies. Finally, with an industrial perspective, I conclude that moving on to bioreactor landfills as an alternative isn't as simple as it may first appear, and that it is a contextually specific solution that must be further refined before replacing current landfills.
ContributorsWhitten, George Avery (Author) / Kavazanjian, Edward (Thesis director) / Allenby, Braden (Committee member) / Houston, Sandra (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2013-05
Description
This study evaluates the use of plant-extracted silica solution as a bio-based grout material for improvement of granular soils. Although silicate grout is a very well-established and popular technique in the ground improvement market, efforts have been initiated to replace chemically-synthesized silicate grout with plant-extracted silica grout. This initiative will increase the level of sustainability and consequently improve the existing market acceptability. The silica-rich plant source used for extraction was rice husk, which is an abundantly produced agricultural waste. The extraction method includes acid-leaching, temperature-controlled rice husk ash production and the preparation of an aqueous sodium silicate solution from the ash through an alkaline leachate method. Silica ash was in amorphous form containing 95% of silica content which is suitable for soil treatment. Gelation time was controlled in the absence and presence of sand under different pH values. Bio-based silica grouting showed an improvement of the shear strength of the soil as well as the hydraulic conductivity reduction.
ContributorsSayed Mostafa, Ahmad (Author) / Zapata, Claudia (Thesis advisor) / Khodadaditirkolaei, Hamed (Thesis advisor) / Kavazanjian, Edward (Committee member) / Arizona State University (Publisher)
Created2019