Study Of Multi-Dimensional Transfer Effects In Applied Smouldering Systems, Seyed Ziaedin Miry Mr

Electronic Thesis and Dissertation Repository

Smouldering is a flameless form of combustion that is driven by oxygen directly diffusing into the surface of condensed phase fuel (liquid or solid) and involves a complex interplay between heat and mass transfer through porous media, chemical reactions, and multiphase flow. Applied smouldering systems have been gaining popularity for a variety of applications including (i) energy and resource recovery, (ii) waste-to-energy, (iii) pyrolysis and gasification, and (iv) applied smouldering of organic liquids/solids for environmental benefits. In all contexts, smouldering is a complicated oxygen-limited phenomenon where multi-dimensional transfer effects (i.e., non-uniformities in …

Performance And Ultimate Limit State Of Large-Span Soil-Steel Structures, Kareem Embaby

Electronic Thesis and Dissertation Repository

This thesis investigates the structural behavior and soil-structure interaction mechanism of large-span soil-steel structures utilizing steel plates with the deepest corrugation profile, 500 mm X 237 mm. The world’s largest-span soil-steel bridge, with a span of 32.40 m, was constructed using 12 mm thick steel plates with the deepest corrugation profile and was instrumented extensively to monitor the displacements and straining actions of the steel structure. Lateral reinforcement steel mesh was attached to the steel structure and the ends of the structure were strengthened by circumferential reinforced concrete collars. Three-dimensional (3D) nonlinear finite element (FE) model was conducted and validated …

Assessment Of Geo-Mechanical Properties Of Lunar Simulants, Devansh Joshi

Electronic Thesis and Dissertation Repository

Abstract

Sophisticated manned and unmanned lunar missions are being developed by international collaborations of the USA, Canada, EU, India, China, Japan etc. for a long-term human presence on the moon. These lunar missions require prototype testing of rovers and other hardware on the earth to successfully interact with the lunar surface. This laboratory testing requires various simulant (terrestrial soil mimicking one or more lunar regolith characteristics) testbeds. Actual lunar soil is too pristine and scarce to be used for destructive testing. Hence, simulants have been developed by research institutions, space research organizations, or commercial manufacturers to cater to a wide …

Performance Of Fouled Railroad Superstructure Subjected To Traversing Heavy Haul Trains, Majid Kh Touqan

Electronic Thesis and Dissertation Repository

Railway transportation offers capacity, efficiency, and safety to serve the needs of modern societies for moving freight and people. Therefore, the sustainability and safety of railroad infrastructure are of paramount importance for securing transportation needs. Freight train passby loads increase the surface deformation of railroad substructure due to cumulative plastic strains, which lead to surface deviation of the railroad tracks. Correspondingly, railroad maintenance is necessary to sustain track geometry alignment and to prevent deterioration of the sub-structure over time, which can increase operating costs significantly. Therefore, this thesis evaluates the performance of fouled railroad superstructure through laboratory testing of fouled …

Static Liquefaction And Critical State Mechanics Of Gold Mine Tailings Subjected To Different Stress Paths, Amir Reza Fotovvat

Electronic Thesis and Dissertation Repository

The mechanisms through which mine tailings fail have been the interests of many studies recently. In this series of studies, the flow liquefaction and instability behavior of gold mine tailings were examined within the framework of critical state soil mechanics. In the first study, the behavior of a gold mine tailings in stress paths involving extensional consolidation or shearing in extension was evaluated. Monotonic tests were carried out on isotropically and K_o-consolidated samples to assess the effect of stress-induced anisotropy and mode of shearing on the static liquefaction characteristics tailings. In the second study, the drained instability of …

Lunar Regolith Simulant Behaviours Affected By Shock Metamorphism And Mineralogy, Xiao Chen Zhang

Electronic Thesis and Dissertation Repository

There are still many gaps in improving the fidelity of lunar regolith simulants to simulate more properties. This study compares some fundamental physical and mineralogical properties of three types of lunar highland regolith simulants: LHS-1, a commercial product with high mineralogical fidelity; UWO-1G, an original simulant that is the main component of LHS-1; and UWO-1S, another original product that is attempted to produce shocked grains in lunar simulants from pulverizing and mixing impact rocks sourced from the Mistastin Crater.

Preliminary results indicated that even though all simulants are composed of mostly plagioclase minerals and have similar particle size distribution patterns, …

Seismic Response Of Driven And Helical Piles In Non-Liquefiable And Liquefiable Soils, Ahmed Fouad Hussein

Electronic Thesis and Dissertation Repository

The thesis investigates the nonlinear soil-pile-structure interaction through three-dimensional nonlinear finite element models (FEM) employing the OpenSees platform. The FEMs were validated with the results of large-scale shaking table tests of model pile groups-superstructure systems in dry and saturated sand and large-scale field tests on single piles installed in cohesive soil. The numerical models correctly predicted the different pile deformation modes that were exhibited in the experiments. The results illustrated that the inertial interaction contributed to the bending moments at the pile top, while the kinematic interaction contributed to the bending moment at the layers interface. In addition, the excess …

Static Liquefaction Of Oil Sand Tailings: An Experimental Investigation Into The Effect Of Saturation And Fines Content, Farshad Zehforoosh

Electronic Thesis and Dissertation Repository

The main goals of this research are to explore the influence of partial saturation and fine content on the shear response of oil sand tailings, to identify the liquefaction susceptibility under different initial states. Monotonic triaxial compression tests were carried out to understand the mechanical behavior of the saturated oil sand tailings with varying void ratios. Then the effect of fine content on the yield and critical shear strength, critical state line, and instability line was evaluated by increasing the fine content up to 50%. The experimental results revealed that the shear strength of the oil sand increases with fine …

Guidelines For Designing The Overhead Transmission Tower Foundations Adjacent To Cohesionless Slopes, Meshel Q. Alkahtani

Electronic Thesis and Dissertation Repository

Foundations supporting electrical transmission line towers are subjected to oblique loading due to tower own weight along with wind loading. Due to land limitation and linear alignment of transmission lines, many power transmission towers are situated in sand near sloping grounds and proper evaluation of their foundation performance is essential for the safety and reliability of the critical power transmission lines. There is currently no guidance available on the behaviour of transmission towers foundations constructed near slopes. Thus, the primary objectives of this study are to evaluate the response of transmission tower foundations in cohesionless sloping grounds and investigate the …

Scaled Physical Modeling Of The Dynamics Of Granular Flow In Hopper Silos, Hagos Eman

Electronic Thesis and Dissertation Repository

To understand the challenges on grain flow during handling in hoppers and silos require better understanding of the granular physical flow characteristics through experiments done at large scale. However, due to the complexity of the large, controlled tests, scaled models are often used to study the behaviour. Very few of these model scale studies had been done appropriately taking the effects of gravity on silo discharge into account. This subject has also been widely investigated in different areas of geotechnical engineering related to soil erosion, land slides, and dynamic liquefaction. Granular flow rate and the dynamics of the flow are …

Performance Of Single And Grouped Helical Piles Under Strong Earthquake Shaking, Abdelrahman F.F. Aly

Electronic Thesis and Dissertation Repository

Full-scale shaking table testing was conducted to evaluate the seismic performance of single and grouped helical piles. Eight circular and one square helical piles with different properties as well as one driven circular pile were installed in dry sand enclosed in a laminar soil shear box that was situated on the shaking table. Dynamic properties of sand bed and its natural frequency, as well as the natural frequencies of single and grouped helical pile-soil systems were evaluated from the collected data during different shaking events. The effects of different pile configurations as well as successive shakings on the characteristics of …

Towards Realistic Simulation Of Penetration Tests And Instability Analysis Of Sand: A Micromechanical Perspective, Seyedshayan Hashemi

Electronic Thesis and Dissertation Repository

In this series of studies, the capability of Discrete Element Method (DEM) to simulate the behavior of granular materials has been examined. In the first study, various boundary conditions are simulated through a series of DEM-based miniature calibration chamber tests to investigate the influence of boundary conditions on cone tip (q_c) and sleeve frictional (f_s) resistances. The second study focuses on the influence of microparameters such as state, modulus, rolling resistance, inter-particle friction, and probe properties on CPT measurements in a centrifuge setting. DEM has been used in the last study to investigate the instability of …

Full-Scale Field Study Of A Geogrid-Reinforced Unpaved Road System, Abdalla El Tawati

Electronic Thesis and Dissertation Repository

Geogrids are widely used to improve the performance of unpaved roads constructed over weak subgrade. However, the behavior of geogrids under traffic loads and their reinforcing mechanisms, as well as the resulting benefits to the roadway performance are not well understood. A full-scale field study was conducted to quantify the effectiveness of geogrids in unpaved roads, evaluate their reinforcing mechanism, and identify which geogrid properties are most directly related to performance improvement. Ten full-scale unpaved road test sections were constructed with varying relevant parameters including geogrid aperture shape, geogrid tensile modulus, and thickness of the base course layer. Five of …

Geo-Structural Analysis Of Integral Abutment Bridges, Biyi Li

Electronic Thesis and Dissertation Repository

Integral abutment bridges are jointless bridges where bridge decks and girders are integrated with abutments. The longitudinal displacements and rotations of the bridge are partially accommodated by the soil-pile system wherein the soil surrounding the piles generates active and reactive lateral forces when the piles deflect due to the movement of the superstructure. Since the soil stress-strain responses are inherently nonlinear, the pile deflection and the soil stiffness are interdependent. Consequently, evaluating soil-pile interactions requires a detailed geo-structural analysis. There are two common approaches used to idealize the soil-pile interactions for laterally loaded piles: the p-y and continuum mechanics approaches …

Biomechanics Of Trees Under Extreme Wind Loading Events, Mojtaba Dargahi

Electronic Thesis and Dissertation Repository

For urban planners, arborists and foresters, understanding tree stability under self-weight and applied loads from wind and snow is important when developing management strategies to reduce the risk of damage from these abiotic agents. Current predictive approaches are generally empirical and based on a posteriori surveys of failures. A more rigorous engineering approach to understanding response phenomenon in trees subjected to extreme winds has been attempted herein. The size of trees and their architecture (shape and structure) greatly influence their mechanical stability under dynamic loading. Considering trees as porous media, wind loads on them are affected by their resistance to …

Ultimate And Serviceability Limit States Of Large Shallow Foundations Under Combined Loading, Pengpeng He

Electronic Thesis and Dissertation Repository

Estimation of the bearing capacity and deformations of large shallow foundations under combined loadings can be of great significance. Some geotechnical design guidelines recommend the failure load envelope method for ultimate limit state analysis. Since many investigations of this method focus primarily on undrained failure envelopes using unlimited-tension interfaces, zero-tension interfaces have not been well investigated. In addition, less work is available on drained failure envelopes. For serviceability limit states, the majority of approaches used are based on uncoupled, isotropic assumptions. Further work needs to be done on more appropriate elastic solutions for combined loadings.

General VHMT failure envelopes for …

Advanced Hardware And Software Approach To Seismic Site Response Investigations, Aleksandar Dimitrov Mihaylov

Electronic Thesis and Dissertation Repository

Vibration measurement is an essential aspect of modern geotechnical engineering. It is particularly vital task for measuring the dynamic soil parameters, estimating seismic hazards and evaluating influence of industrial, traffic and construction vibrations on the surrounding buildings, structures and their elements. Meanwhile, commercial exploration seismic stations and data acquisition systems require significant professional knowledge and training in geophysics or vibration measurement, as well as practical skills and experience in adjusting data acquisition parameters. Furthermore, available seismological investigation and vibrometry sensors are not universally suitable for field applications in geophysical studies, soil-structure interaction investigations or structural vibrations. The frequency range suitable …

System Reliability Analysis Of Defected Pile Group Foundations, Abdalla E. Adlan Alhashmi

Electronic Thesis and Dissertation Repository

Deep foundations design suffers some degrees of uncertainties. This thesis studies the behavior of defected pile group foundations installed in sand and calibrates the resistance factor of pile group foundation, utilizing a rational based system reliability analysis. This was achieved by conducting a comprehensive numerical parametric investigation using the computer program ABAQUS/Standard. The result of the parametric study showed that the presence of a defected pile in a pile group foundation causes lateral deflection of the pile cap and hence induces bending moment at the adjacent piles which affects the load distribution mechanism of the system. It was also found …

Miniature Cone Penetration Tests With Shear Wave Velocity And Electrical Resistivity Measurements In Characterization Of Silica Sand, Ronit Ganguly

Electronic Thesis and Dissertation Repository

Geotechnical engineering design and analysis require sound identification and characterization of in-situ soil. To characterize is to gather information about the engineering properties of a particular soil which will affect the performance of any structure built on it. As a result of complications associated with the retrieving of undisturbed samples of cohesionless soils, calibration chamber-based experiments under controlled laboratory settings are used for the determination of several geotechnical engineering parameters. The capability of a reduced-scale calibration chamber-based cone penetration testing system along with shear wave velocity and electrical resistivity measurements, to better characterize in-situ soil is examined in this study. …

High Strain Dynamic Test On Helical Piles: Analytical And Numerical Investigations, Mohammed Fahad Alwalan

Electronic Thesis and Dissertation Repository

Helical piles are currently considered a preferred foundation option in a wide range of engineering projects to provide high compressive and uplift resistance to static and dynamic loads. In view of the large capacity of large diameter helical piles, there is a need to determine their capacity using accurate and economically feasible testing techniques. The capacity of piles is usually determined by conducting a Static Load Test (SLT). However, the SLT can be costly and time consuming, especially for large capacity piles. The High Strain Dynamic Load Test (HSDT) evaluates the pile capacity using dynamic measurements generated through subjecting the …

Prediction Of Static Liquefaction Landslides, Abouzar Sadrekarimi

Civil and Environmental Engineering Presentations

Static liquefaction failure of sloping grounds has resulted in significant damages to built structures and even loss of lives. The principal aim of this research is to relate static liquefaction behavior of cohesionless soils to a measurable threshold from the field. Based on a very large number (893) of undrained laboratory shear tests on cohesionless soils collected from the past literature, a threshold triggering excess pore water pressure is introduced in this study above which static liquefaction failure occurs. The effect of variations in the direction and relative magnitudes of principal stresses associated with different modes of shear and ground …

Experimental And Numerical Evaluation Of A Novel Piling System For Sound Wall Applications, Daniel Mroz

Electronic Thesis and Dissertation Repository

Drilled shafts are conventionally used as foundations for sound walls. However, steel piles can provide faster installation and immediate utilization. The purpose of this research program is to evaluate a novel pile concept which comprises an H-pile modified to better resist typical load patterns faced by sound wall piles including lateral force and moment from wind and uplift force from adfreeze. The modifications include one or two plates welded to the pile and soil anchors (nodes) welded along the pile flange.

A full-scale pile load testing program was performed on sixteen piles which included monotonic and cyclic lateral load tests …

The Effect Of Stiffness Anisotropy Of A Glacial Clay On The Behaviour Of A Shallow Wind Turbine Foundation, Jesús A. González-Hurtado

Electronic Thesis and Dissertation Repository

Shallow wind turbine foundations are designed based on investigations of the ultimate, serviceability and fatigue limit states. The serviceability limit state design approaches in particular are based on simple isotropic elastic half-space analyses that ignore coupling between loading directions, and soil non-linearity and elastic anisotropy. Many of the wind farms in Ontario are constructed around the Great Lakes basin and a number of these areas are characterized as stiff clayey glacial tills. It is recognized that many of these glacial materials exhibit some degree of strength, stiffness and fabric anisotropy. This research aimed to characterize the anisotropic geotechnical properties of …

Studies On The Liquefaction Behaviour Of Tailings And Natural Sand, Guillermo Riveros

Electronic Thesis and Dissertation Repository

This series of studies explores the liquefaction behaviour of cohesionless mine tailings and a natural sand and examines the effectiveness of a bio-mediated treatment for the mitigation of liquefaction. The first study investigates the flow liquefaction failure of the Fundão tailings dam (2015) by analytically assessing the stability of the breached abutment, accounting for the specific triggering mechanism and subsequent strength loss that led to its collapse. The second study evaluates the static liquefaction behaviour of gold mine tailings and its correlations with shear-wave velocity through an experimental program comprised of direct simple-shear and bender element tests. The last study …

Performance Of Pressure Grouted Helical Piles Under Monotonic Axial And Lateral Loading, Mohamed A. Mansour

Electronic Thesis and Dissertation Repository

The pressure grouted helical pile (PGHP) is an innovative pile foundation system that allows a significant increase in the helical pile capacity with some additional cost. The pile is constructed by applying pressurized grout during the installation of a closed ended helical pile through two grout nozzles welded to the hollow pile shaft. Torquing PGHP into the ground allows the grout nozzles to create a cavity around the pile shaft. The cavity then expands under the effect of pressurized grout and helix rotation. This thesis presents a comprehensive laboratory study and three-dimensional finite element analysis to investigate the effects of …

Seismic Landslide Hazard Mapping For Greater Vancouver, British Columbia, Ali Fallah Yeznabad, Sheri E. Molnar, Hesham M. El Naggar

Western Research Forum

The lower Mainland of southwest British Columbia (BC) hosts about 3.5 million people and significant infrastructures of national importance. Southwestern BC has the highest seismic risk in Canada with significant potential to cause earthquake-induced hazards including tsunamis, liquefaction and landslides. A Cascadia mega-thrust (M_W 9) earthquake is predicted to generate $75 billion Canadian dollars in losses. This damage can be resulted from ground shaking or its secondary phenomena like landslides; ground shaking during earthquakes may trigger landslides that can damage or destroy buildings, bury roads and highways and kill and injure people. In Canada, during the past century and …

Advances In Design Methodology In Swelling Shale Rock In Southern Ontario, Thomas R.A. Lardner

Electronic Thesis and Dissertation Repository

As infrastructure requirements increase in southern Ontario, excavations within swelling rock formations will become more frequent and larger. The objective of this study is to advance design capability for structures in swelling rock through three aspects: i) developing a practical swelling model for design engineers, ii) investigate two crushable/compressible materials for the mitigation of swelling rock effects, and iii) observe and analyze the behaviour of swelling rock to current excavation techniques.

A swelling rock constitutive model has been developed. The swelling parameters include the horizontal and vertical free swell potential, threshold stress, and critical stress as well as a “pseudo-Poisson’s …

Robust Earthquake Site Classification Assessment At Ontario Bridge Sites., Alex Bilson Darko

Electronic Thesis and Dissertation Repository

Canadian seismic design guidelines classify subsurface ground conditions based on the average shear-wave velocity (V_S) of the upper 30 meters (V_S30). We seek to optimize a robust earthquake site classification procedure for Ontario bridge sites, assessed primarily from blind comparison of non-invasive V_S depth profiling techniques. Non-invasive seismic testing is performed at 10 bridge sites in southern Ontario co-located with invasive penetration and/or borehole V_S measurements. Non-invasive surface wave dispersion and site amplification functions are jointly inverted to retrieve V_S profiles at each site. A general correlation between corrected V_S and cone …

Monotonic Stress-Strain Behaviour Of Fibre Reinforced Cemented Toyoura Sand, Muhammad Safdar

Electronic Thesis and Dissertation Repository

The Great East Japan earthquake of 2011 generated a huge quantity of disaster waste and tsunami deposits, which required proper treatment and disposal. To effectively use these waste soils in geotechnical applications, it is essential to understand the mechanical behaviour in their native (pure) or mechanically stabilized form (amended with cement and fibre). To address these objectives, a series of monotonic stress-strain (e.g. compression and extension) triaxial drained and undrained tests were performed on pure Toyoura sand and mixtures of Toyoura sand-silt-cement-fibre. Additional laboratory studies were performed to investigate other related aspects, such as density, back pressure, small-strain elasticity, curing …

A Study On Chemical Grouting Of Quartz Sand, Bingfeng Xue

Electronic Thesis and Dissertation Repository

Chemical grouting has been used in engineering projects for decades. The primary objectives of chemical grouting in geotechnical engineering projects are to increase the soil strength, to decrease the soil permeability, and to control deformations of in-situ soil. In the design and applications of chemical grouting, laboratory testing of chemical grouted samples is an important step for the feasibility assessment.

The advantages of sodium silicate grout include high penetrability, flexible set times, and environmentally friendly, which makes it one of the most employed grouts in applications. Recently, an innovative sodium silicate, which has the silica to alkali ratio of 4.5 …