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Two field studies of surface displacements during pipe bursting were conducted. The first field study consisted of a controlled experiment in clay soil. Three vitrified clay pipelines, each at a different burial depth, were up-sized to high density polyethylene (HDPE) pipes using static pipe bursting techniques. Surface displacements during the pipe bursting process were monitored using digital imaging techniques as well as surveying. It was found that ground displacements were largest in the vertical direction, such that the maximum vertical displacements measured during pipe bursting ranged from 71.8 ± 7.5 mm at a depth of cover of 0.6 m and 11.2 ± 1.2 mm at a depth of cover of 1.5 m. Transverse displacements generated during pipe bursting were found to correspond to tension cracking of the ground surface above the pipe. The second field study examined pipe bursting installations which took place at the Royal Canadian Mounted Police College campus in Ottawa, Ontario. During this study, five pipe bursting installations were monitored. Each installation varied in terms of the surface and subsurface conditions, host pipe size and material, replacement pipe size, and depth of cover. The pattern of displacements distributed in all three directions was consistent with the results from the controlled study. However, greater variability in results was found during the Ottawa project. Vertical displacements were found to range from 0.6 ± 0.1 mm to 11.3 ± 0.2 mm for pipe bursts carried out to the same up-size dimension, at approximately the same depth of cover, surrounded by similar surface and subsurface conditions. In general, pipe bursting in clayey soils with an unpaved surface resulted in larger displacements having a narrower distribution over the ground surface than the paved installations. Additionally, increased variability in results occurred under real construction conditions due to inherent variability in subsurface and host pipe conditions. / Thesis (Master, Civil Engineering) -- Queen's University, 2008-12-23 12:52:08.301

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Η παρούσα διδακτορική διατριβή πραγματεύεται τις παραμένουσες μετακινήσεις κατασκευών υπό σεισμικές δράσεις, με στόχο την πληρέστερη κατανόηση και ποσοτικοποίησή τους. Για τον υπολογισμό των παραμενουσών μετακινήσεων πραγματοποιήθηκαν μη-γραμμικές δυναμικές αναλύσεις μονοβάθμιων συστημάτων, δίνοντας ιδιαίτερη έμφαση στη μορφή του νόμου υστέρησης, ώστε να έχει τα χαρακτηριστικά που προσιδιάζουν σε κατασκευές οπλισμένου σκυροδέματος. Συγκεκριμένα, υιοθετήθηκε η κατηγοριοποίηση των κατασκευών ΟΣ κατά Erberik (2011) σε τρεις βασικές Κατηγορίες, ανάλογα με την υστερητική τους συμπεριφορά: (α) νέα κτίρια, σχεδιασμένα με σύγχρονους αντισεισμικούς κανονισμούς, (β) κτίρια που δεν καλύπτουν πλήρως τους σύγχρονους αντισεισμικούς κανονισμούς και (γ) παλαιά κτίρια που δεν διαθέτουν σεισμική αντοχή. Για λόγους σύγκρισης εξετάστηκε και η ιδανική υστερητική συμπεριφορά. Η παραμένουσα μετακίνηση κάθε συστήματος, Ures, κανονικοποιήθηκε ως προς τη μέγιστη μετακίνηση που θα είχε λάβει το σύστημα αν η απόκρισή του ήταν ελαστική, με 5% απόσβεση, Sd, αλλά και ως προς τη μέγιστη ανελαστική μετακίνηση του συστήματος, Umax. Οι λόγοι Ures/Sd και Ures/Umax μελετήθηκαν εκτενώς και αναπτύχθηκαν πιθανοτικά προσομοιώματα για τα φάσματα ανηγμένων παραμενουσών μετακινήσεων που προέκυψαν. Επιπλέον, διαπιστώθηκε η επίδραση της ύπαρξης παλμού στην εδαφική κίνηση στους λόγους Ures/Sd και Ures/Umax, και διερευνήθηκαν οι λόγοι της επιρροής του. Περαιτέρω, οι πειραματικές παραμένουσες μετακινήσεις πέντε τριώροφων επίπεδων πλαισίων ΟΣ που υποβλήθησαν σε ψευδοδυναμικές δοκιμές με εξωτερικά επιβαλλόμενα κατακόρυφα φορτία στο METU (Middle East Technical University) συσχετίστηκαν με τις αναλυτικές από μη-γραμμικές δυναμικές αναλύσεις χρονοϊστορίας. Εξετάστηκε αν τα διαθέσιμα υπολογιστικά εργαλεία ανάλυσης δύνανται να υπολογίσουν ικανοποιητικά τις παραμένουσες μετακινήσεις, αλλά και ποιοι παράγοντες ευθύνονται για τις ασυμφωνίες μεταξύ πειραματικών και αναλυτικών τιμών. Τέλος, οι λόγοι Ures/Sd και Ures/Umax που προέκυψαν από την ανάλυση των δοκιμίων και από την επεξεργασία των πειραματικών αποτελεσμάτων συγκρίθηκαν με τα φάσματα ανηγμένων παραμενουσών μετακινήσεων μονοβάθμιων συστημάτων. / The present study aims to evaluate and quantify seismic residual displacements. In order to compute residual displacements, non-linear dynamic analyses were conducted for single degree of freedom systems with cyclic force-deformation relations typical of reinforced concrete structures. To this end, the versatile modeling approach of Erberik (2011) was adopted, which was tuned to three different categories of RC structures, ranging from new earthquake resistant ones to existing substandard construction, with an intermediate situation. The ideal hysteretic behavior was also examined. For each single degree of freedom system, residual displacement, Ures, was expressed as ratio to the peak inelastic, Umax or the 5%-damped elastic displacement of the response, Sd. Ratios Ures/Sd and Ures/Umax were thoroughly studied and normalized residual displacements response spectrums were created. Moreover, it was noted that the existence of a distinct velocity pulse in the ground motion affects the magnitude of these ratios, and the reasons of this influence were further investigated. Furthermore, experimental residual displacements from five three-story reinforced concrete frames, which were subjected to pseudo-dynamic tests in METU (Middle East Technical University), were compared to analytical residual displacements from non-linear time-history analyses. The study focused on whether modern analysis tools can accurately predict residual displacements and which factors create the observed discrepancies between analytical and experimental values. Lastly, ratios Ures/Sd and Ures/Umax from experiments and time-history analyses were compared to the normalized residual response spectrums of single degree of freedom systems.

Baigiamajame magistro darbe, kuris atliktas pagal VGTU, Statybos fakulteto, Geotechnikos katedros pateiktą užduotį, atliktas geosintetinių medžiagų taikymo pagrindo stiprinimui galimybės vertinimas. Darbą, kurio tema „Pagrindo stiprinimas naudojant geosintetinę armatūrą“, sudaro supažindinimas su geosintetikos sąvoka, pagrindinių gaminių pavyzdžių ir jiems gaminti naudojamų žaliavų aprašymas ir taikymo sričių aprašymas, geosintetinių gaminių ilgaamžiškumo ir destrukcijos nagrinėjimas, realiai įgyvendintų statybos projektų Lietuvoje apžvalga, geosintetikos darbo grunte nagrinėjimas ir literatūros šaltinių analizė, pateikiamos dažniausiai taikomos geosintetikos skaičiavimo metodikos. Pagrindinės darbo dalys yra eksperimentinis tyrimas horizontalių grunto deformacijų priklausomybei nuo armavimo tipo nustatymas, jo kompiuterinis modeliavimas programiniu paketu „Plaxis“ bei vokiečių standarto DIN skaičiavimo metodikos sekliojo pamato galios nustatymui nagrinėjimas ir analogiškos situacijos rezultatų gautų kompiuterinio modeliavimo programa „GEO5“ palyginimas. Darbe pateikiami atliktų eksperimentų metodikų aprašymai, nuotraukos iš tyrimo vietų bei gauti rezultatai ir jais paremtos išvados bei rekomendacijos. / The Masters thesis has been done by the tasks of the Department of Civil Engineering of Vilnius Gediminas Technical University. Thesis, titled „Ground reinforcement using geogrids“, contains introduction of geosynthetics conception, description of main products and raw materials used in manufacture process, analysis of geosynthetics‘ durability and destruction, overview of construction projects with geosynthetics used in Lithuania, analysis of geosynthetics‘ and soils‘ performance, investigation and analysis of usually used geosynthetics designing methodology. The main parts of the work is an experimental study of horizontal ground deformation dependence on reinforcement type, the computer simulation with program package „Plaxis“ and analysis of German DIN standard calculation methodology for shallow foundation bearing capacity on reinforced subgrade and results comparison with ones obtained by computer simulation program „GEO5“. The paper presents the methodologies and descriptions of carried experiments, photos from test sites, conclusions and recommendations based on obtained results.

Mixing of miscible gas with oil in a reservoir decreases the effective strength of the gas, which can adversely affect miscibility and recovery efficiency. The mixing that occurs in a reservoir, however, is widely debated and often ignored in reservoir simulation, where very large grid blocks are used. Large grid blocks create artificially large mixing that can cause errors in predicted oil recovery. Reservoir mixing, or dispersion, is caused by diffusion of particles across streamlines of varying velocities. Mixing is enhanced by any mechanism that increases the area of contact between the gas and the oil, thereby allowing the effects of diffusion to be magnified. This is, in essence, the cause of scale-dependent dispersion. The contact area grows primarily because of variations in streamlines and their velocities around grains and through layers of various permeabilities (heterogeneity). Mixing can also be enhanced by crossflow, such as that caused by gravity and by the effects of other neighboring wells. This dissertation focuses on estimation of the level of effective local mixing at the field scale and its impact on oil recovery from miscible gas floods. Pore-level simulation was performed using the Navier-Stokes and convection-diffusion equations to examine the origin of scale dependent dispersion. We then estimated dispersivity at the macro scale as a function of key scaling groups in heterogeneous reservoirs. Lastly, we upscaled grid blocks to match the level of mixing at the pattern scale. Once the contact area ceases to grow with distance traveled, dispersion has reached its asymptotic limit. This generally occurs when the fluids are well mixed in transverse direction. We investigated a variety of pore-scale models to understand the nature of scale dependency. From the pore-scale study, we found that reservoir mixing or dispersion is caused by diffusion of particles across streamlines. Diffusion can be significantly enhanced if the surface area of contact between the reservoir and injected fluid are increased as fluids propagate through the reservoir. Echo and transmission dispersivities are scale dependent. They may or may not reach an asymptotic limit depending on the scale of heterogeneities encountered. The scale dependence results from an increase in the contact area between solute (gas) and resident fluid (oil) as heterogeneities are encountered, either at the pore or pattern-scale. The key scaling groups for first-contact miscible (FCM) flow are derived and their impact on mixing is analyzed. We examine only local mixing, not apparent mixing caused by variations in streamline path lengths (convective spreading). Local mixing is important because it affects the strength of the injected fluid, and can cause an otherwise multicontact miscible (MCM) flood to become immiscible. We then showed how to upscale miscible floods considering reservoir mixing. The sum of numerical dispersion and physical dispersion associated with the reservoir heterogeneities, geometry and fluid properties must be equal at both the fine- and large-scales. The maximum grid-block size allowed in both the x- and z-directions is determined from the scaling groups. Small grid-blocks must be used for reservoirs with uncorrelated permeabilities, while larger grid blocks can be used for more layered reservoirs. The predicted level of mixing for first-contact miscible floods can be extended with good accuracy to multicontact miscible (MCM) gas floods. / text

This project examines the spatial relationships that exist between Winnipeg, Canada and Tokyo, Japan, with the intent to develop an understanding of the preciseness of the world. Different site-specific systemic conditions were used as critical tools to explore the implication of distinct design catalysts and inhibitors. I have concentrated on the relationships that exist between time and space, to identify and displace localized, momentary events that exist in one site to the other. Familiarities of my local surroundings were deliberately obscured to make explicit a heightened awareness of my position on the planet. This helps to facilitate discussions. I have created a space that is dissembled through abstract understandings of displaced elements in the environment. It is my intention for this space to be experienced in a different way each time we come across it, by shifting and changing ones perception of their character in the world. / October 2008

This project examines the spatial relationships that exist between Winnipeg, Canada and Tokyo, Japan, with the intent to develop an understanding of the preciseness of the world. Different site-specific systemic conditions were used as critical tools to explore the implication of distinct design catalysts and inhibitors. I have concentrated on the relationships that exist between time and space, to identify and displace localized, momentary events that exist in one site to the other. Familiarities of my local surroundings were deliberately obscured to make explicit a heightened awareness of my position on the planet. This helps to facilitate discussions. I have created a space that is dissembled through abstract understandings of displaced elements in the environment. It is my intention for this space to be experienced in a different way each time we come across it, by shifting and changing ones perception of their character in the world.

No description available.

This project examines the spatial relationships that exist between Winnipeg, Canada and Tokyo, Japan, with the intent to develop an understanding of the preciseness of the world. Different site-specific systemic conditions were used as critical tools to explore the implication of distinct design catalysts and inhibitors. I have concentrated on the relationships that exist between time and space, to identify and displace localized, momentary events that exist in one site to the other. Familiarities of my local surroundings were deliberately obscured to make explicit a heightened awareness of my position on the planet. This helps to facilitate discussions. I have created a space that is dissembled through abstract understandings of displaced elements in the environment. It is my intention for this space to be experienced in a different way each time we come across it, by shifting and changing ones perception of their character in the world.