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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Framework for design of geosynthetic reinforced segmental retaining walls

Kang, Beongjoon 11 April 2014 (has links)
<p>This thesis is concerned with a design-oriented formulation of reinforced Segmental Retaining Wall (SRW) structures. The formulation follows the concept of the safety map used in slope stability analysis. It calculates the minimum tensile force requirement along each reinforcement layer by utilizing limit equilibrium method with log spiral surface. In the formulation, the force in the reinforcement at each location produces a limit equilibrium state. It considers the pullout capacity of each reinforcement layer. Consequently, the required distribution of tensile force along each layer is produced rendering a baseline solution for design. The calculated tensile force distribution considers the required force and pullout resistance of all other layers. Hence, it produces an optimized system where failure is equally likely to occur at any point within the reinforced soil mass. The developed framework enables one to decide the required strength of the connection between the reinforcement and the facing. Extensive parametric studies were carried out to evaluate the effect of the each component comprising the system. The parametric studies consider the wall geometry, the quality of backfill, the length and spacing of reinforcement, the effects of intermediate layers, the pullout resistance, the coverage ratio, the toe resistance, and the impact of seismic loading. Verification of the analytical framework was conducted through comparison with some records of full-scale and centrifuge experiments. Design implications are presented through some examples.
42

The effect of geology on fragmentation in small development headings

Doucet, Chantale January 1995 (has links)
This thesis presents the results of a research project on the effect of geology on the fragmentation of rock excavated by blasting in underground developments. The research was undertaken at CANMET's Experimental Mine in Val-d'Or, Quebec. / A total of thirteen (13) blasts were studied from November 1994 to February 1995. The analysis of each blast was divided into three stages: (1) Pre-blast: includes structural mapping, rockmass characterization, estimation of the in situ block size distribution and documentation of the blast design. (2) Blast: includes blast vibration monitoring and analysis. (3) Post-blast: includes determination of fragment size distribution, half-cast factors and bootlegs. / The blast design was kept as constant as possible throughout the study in order to limit the variation of parameters to the geology-related ones. The results were analyzed to determine any correlation between the rockmass characteristics and the blast results. Only general trends were found: (1) The characteristic size of the fragments obtained after blasting (x$ rm sb{c}$ blast) increases when the characteristic size of the in situ distribution (x$ rm sb{c}$ in situ) increases; (2) The characteristic size of the fragments obtained after blasting (x$ rm sb{c}$ blast) decreases when the adjusted powder factor increases; (3) The half-cast factor (HCF) decreases when the Rock Quality Designation (RQD), RMR and Q values increase; (4) The characteristic size of the fragments obtained after blasting (x$ rm sb{c}$ blast) increases when the RQD, Rock Mass Rating (RMR) and quality index (Q) values increase. / Some of these results confirm basic blasting principles whereas others were unexpected. The fact that no statistical correlation could be found is probably due to the geological environment in which the experiments were completed. The rock types encountered have very similar mechanical properties and the quality of the rockmasses did not vary extensively. Therefore, any variance in the results is best explained by the blast performance itself. (Abstract shortened by UMI.)
43

A study of frictional properties of rock masses /

Hadjigeorgiou, John January 1987 (has links)
The design of traditional and novel structures, e.g. underground tunnels, dam foundations, nuclear waste depositories, requires an understanding of the behaviour of rock under different stress conditions. This thesis is part of an overall research program into the behaviour of rock masses undertaken by the Department of Mining and Metallurgical Engineering at McGill University. The main objective of this project is the determination of the appropriate stress functions that describe the response of rock to applied loads. In this work, the distinction is made between intact, single discontinuity and fractured rock material. / The first segment of this thesis deals with a critical evaluation of the different failure criteria for rock and rock discontinuities that have been used in the past. Their applications and limitations are identified. In the second segment of this work, the frictional behaviour of rock and rock discontinuities is defined, based on results of laboratory testing in direct-shear and triaxial compression.
44

Elasto-viscoplastic modelling of rock excavations

Rizkalla, Maged Kamal January 1991 (has links)
The first part of the thesis describes the concepts of viscoplasticity as a continuous plasticity theory highlighting different kinds of yield functions, plastic potentials and visocplastic constitutive laws. / A 2-dimensional elasto-viscoplastic finite element model for stress/stability analysis of mining excavations has been developed for use on microcomputers. An iterative explicit time stepping scheme is implemented. The program uses automatic time-step calculator based on equations giving a limit on the time step in an attempt to prevent numerical instability when common forms of isotropic yield functions and plastic potentials are used in the viscoplastic solution. When the input data are read parallel to the analysis undertaken the user can simulate compound behaviour by stopping the analysis, examining the results graphically and restarting it again and possibly implementing a certain decision in the subsequent appended input. This also imposes no limit on the number of time stations at which instantaneous changes like elements cut, elements backfilled, loads added or simply outputs are required. The program is equipped with graphical pre- and post- processors.
45

Use of cone penetration testing in the interpretation of ground shaking from paleoliquefaction evidence /

Newman, Erik J., January 2007 (has links)
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1183. Adviser: Timothy D. Stark. Includes bibliographical references (leaves 206-214) Available on microfilm from Pro Quest Information and Learning.
46

Three-dimensional discrete element simulation of granular materials using polyhedral particles /

Ghazi-Nezami, Erfan, January 2007 (has links)
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 68-07, Section: B, page: 4672. Adviser: Youssef M. A. Hashash. Includes supplementary digital materials. Includes bibliographical references (leaves 206-213) Available on microfilm from Pro Quest Information and Learning.
47

Detection automatique des changements du bati en milieu urbain sur des images a tres haute resolution spatiale (Ikonos et QuickBird) en utilisant des donnees cartographiques numeriques.

Bouziani, Mourad. Unknown Date (has links)
Thèse (Ph.D.)--Université de Sherbrooke (Canada), 2007. / Titre de l'écran-titre (visionné le 1 février 2007). In ProQuest dissertations and theses. Publié aussi en version papier.
48

Applications of Nanotechnology in Geotechnical Engineering

January 2016 (has links)
abstract: 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. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2016
49

The angles of friction of granular fills

Lee, Da-Mang January 1992 (has links)
No description available.
50

Utilizing geographic information systems (GIS) for the modeling of warm season soil loss in eastern Ontario, Canada

Wilkes, Graham A January 2004 (has links)
Soil loss in eastern Ontario is of great concern. The objective of this study is to map soil loss risk in Eastern Ontario for 2001. The universal soil loss equation (LISLE), the universal soil loss equation 2 dimensions (USLE2D), and the unit stream power erosion deposition (LISPED) models are applied within a Geographic Information System (GIS) to calculate soil loss within agricultural fields. Hourly precipitation, soil survey, digital elevation, field boundary, and satellite imagery data are main inputs used to generate model parameters at non-depositional areas. These datasets are integrated to compute mean annual and monthly soil loss at multiple scales. For precision agriculture purposes, results are given as a number of high precision, high accuracy soil loss grids and associated summary tables under a variety of farming practices and erosion processes. Results indicate that: (1) soil loss is occurring at intolerable levels (>6 t ha-1 yr -1) in the region, particularly in the southeastern study region, (2) slope steepness followed by the cropping and management factor affect soil loss to the greatest extent, and (3) under no tillage systems, a considerable amount of soil is lost at intolerable levels in high slope areas. (Abstract shortened by UMI.)

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