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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.
1

Η γεωδαιτική μέθοδος ελέγχου παραμορφώσεων σηράγγων: τεκμηρίωση της μεθόδου και ανάλυση παρατηρήσεων / Geodetic monitoring of tunnel deformation: methodology assessment and data analysis

Κοντογιάννη, Βάϊα 22 June 2007 (has links)
Η εφαρμογή των γεωδαιτικών μεθόδων στη χάραξη και παρακολούθηση των υπογείων έργων ακολουθεί σε γενικές γραμμές μια συγκεκριμένη πρακτική η οποία όμως (1) δεν έχει τεκμηριωθεί ως προς την ακρίβεια και τα όρια εφαρμογής της, και (2) τα στοιχεία που συλλέγονται στα διάφορα έργα στη συντριπτική τους πλειοψηφία δεν αξιολογούνται ή αξιοποιούνται. Η παρούσα Διατριβή στοχεύει να συνεισφέρει στο διπλό αυτό στόχο και γι’ αυτό περιλαμβάνει δύο βασικές ενότητες: Η πρώτη ενότητα στοχεύει στην τεκμηρίωση της ακρίβεια της γεωδαιτικής μεθόδου με βάση αναλυτική και πειραματική προσέγγιση και διερευνάται η ποιότητα και η αξιοπιστία διαθέσιμων παρατηρήσεων από αριθμό υπογείων έργων. Ειδικότερα, υπολογίστηκε η ακρίβεια χάραξης σηράγγων, ανάλογη του κύβου του πλήθους στάσεων σκόπευσης. Στη συνέχεια εκτιμήθηκαν οι αναλυτικές ακρίβειες στον υπολογισμό των οριζοντίων και κατακορύφων μετακινήσεων και συγκλίσεων κατά την παρακολούθηση σηράγγων και πραγματοποιήθηκαν πειραματικές μετρήσεις για την ακρίβεια των γεωδαιτικών οργάνων και μεθόδων που εφαρμόζονται. Με βάση τα αποτελέσματα η γεωδαιτική μέθοδος κρίνεται επαρκής και ακριβής για τη χάραξη και παρακολούθηση των συνήθων σηράγγων. Η δεύτερη ενότητα, βασισμένη σε παρατηρήσεις από διάφορες σήραγγες, στοχεύει στον έλεγχο της κινηματικής σημείων ή διατομών ελέγχου σηράγγων, τον έλεγχο των γεωμετρικών χαρακτηριστικών συγκλίσεων αλλά και της τυπολογίας της χρονικής εξέλιξης των μετακινήσεων. Αναλύθηκαν περιπτώσεις χωροχρονικής εξέλιξης μετακινήσεων που αποκλίνουν από την τυπική μορφή, με βασικό χαρακτηριστικό την εμφάνιση απότομων, ανεξήγητων μετακινήσεων. Ειδικότερα, η ανάλυση των διαθέσιμων στοιχείων από τις σήραγγες Τυμφρηστού, Καλλιδρόμου κ.α. οδήγησε στο συμπέρασμα ότι η υπερβολική αύξηση των μετακινήσεων τοπικά σε μια περιοχή προκαλεί κάτω από ορισμένες συνθήκες αλυσιδωτά νέες μετακινήσεις σε γειτονικές, προσωρινά σταθεροποιημένες περιοχές του έργου. / Geodetic techniques are widely used for the guidance and monitoring of underground structures, but (1) their accuracy and efficiency are not tested and (2) deformation data, collected during tunnel excavation, are not further evaluated. A contribution towards the solution of both these problems is the aim of this dissertation, which consists of two parts. In the first part the applicability and accuracy of the geodetic techniques were assessed using analytical and experimental techniques. Three main conclusions were obtained. First, that the errors of coordinates along a tunnel are proportional to the cube of the number of stations. Second, it was found that non-prismatic reflectors have a non-linear response and contributes to significant errors (>1-2mm) in convergence measurements and third, that the noise of actual monitoring measurements from several tunnels is at maximum ±4mm. In the second part of this dissertation deformation data from a number of tunnels were analyzed. Analytical methodologies were introduced for the estimation of the geometrical pattern of tunnel section distortion and mathematical, function approximation techniques are followed to model the typical pattern of tunnel deformation. Studies of monitoring data from tunnels that faced instabilities and high deformation (as Tymfristos tunnel, Kallidromo tunnel etc.) revealed that high tunnel closure locally, may induce a new phase of deformation to other nearby, previously stabilized, sections.
2

Vybudování a zaměření geodetické sítě bodů pro potřeby sledování dlouhodobých změn krajiny. / Establishing and surveying of net of geodetic points for the purpose of long-term changes in landscape.

ŠEVČÍK, Milan January 2008 (has links)
The work is intent on the aplication of useful geodetic method for height off-road treads. The aim of the work is to survey and establish fixed point network for this monitoring. The teoretic part is intent on geodetic network and point fields and on aplication of geodetic method for geodetic monitoring throughout the country. In the practical part, there are described accessible methods for height profiles, description of choice method workmaship and grafic results processing.
3

Contribui??o da Geod?sia ao monitoramento costeiro do Litoral Setentrional do Rio Grande do Norte, ?rea de influ?ncia da ind?stria petrol?fera

Santos, Marcelo Soares Teles 08 July 2011 (has links)
Made available in DSpace on 2014-12-17T14:09:13Z (GMT). No. of bitstreams: 1 MarceloSTS_TESE.pdf: 2868959 bytes, checksum: f60bedf5f558e2aafe77046674684c88 (MD5) Previous issue date: 2011-07-08 / The general objective of this thesis has been seasonal monitoring (quarterly time scale) of coastal and estuarine areas of a section of the Northern Coast of Rio Grande do Norte, Brazil, environmentally sensitive and with intense sediment erosion in the oil activities to underpin the implementation of projects for containment of erosion and mitigate the impacts of coastal dynamics. In order to achieve the general objective, the work was done systematically in three stages which consisted the specific objectives. The first stage was the implementation of geodetic reference infrastructure for carrying out the geodetic survey of the study area. This process included the implementation of RGLS (Northern Coast of the RN GPS Network), consisting of stations with geodetic coordinates and orthometric heights of precision; positioning of Benchmarks and evaluation of the gravimetric geoid available, for use in GPS altimetry of precision; and development of software for GPS altimetry of precision. The second stage was the development and improvement of methodologies for collection, processing, representation, integration and analysis of CoastLine (CL) and Digital Elevation Models (DEM) obtained by geodetic positioning techniques. As part of this stage have been made since, the choice of equipment and positioning methods to be used, depending on the required precision and structure implanted, and the definition of the LC indicator and of the geodesic references best suited, to coastal monitoring of precision. The third step was the seasonal geodesic monitoring of the study area. It was defined the execution times of the geodetic surveys by analyzing the pattern of sediment dynamics of the study area; the performing of surveys in order to calculate and locate areas and volumes of erosion and accretion (sandy and volumetric sedimentary balance) occurred on CL and on the beaches and islands surfaces throughout the year, and study of correlations between the measured variations (in area and volume) between each survey and the action of the coastal dynamic agents. The results allowed an integrated study of spatial and temporal interrelationships of the causes and consequences of intensive coastal processes operating in the area, especially to the measurement of variability of erosion, transport, balance and supply sedimentary over the annual cycle of construction and destruction of beaches. In the analysis of the results, it was possible to identify the causes and consequences of severe coastal erosion occurred on beaches exposed, to analyze the recovery of beaches and the accretion occurring in tidal inlets and estuaries. From the optics of seasonal variations in the CL, human interventions to erosion contention have been proposed with the aim of restoring the previous situation of the beaches in the process of erosion. / O objetivo geral desta Tese de Doutorado foi o monitoramento costeiro sazonal (em escala temporal trimestral) de ?reas costeiras e estuarinas de um trecho do Litoral Setentrional do Estado do Rio Grande do Norte, Brasil, sens?vel ambientalmente e de intensa eros?o sedimentar sob as atividades petrol?feras, para servir de base na implanta??o de projetos de conten??o da eros?o e na mitiga??o dos impactos causados pela din?mica costeira. Para atingir o objetivo geral, o trabalho foi desenvolvido de maneira sistem?tica em tr?s etapas, as quais consistiram os objetivos espec?ficos. A primeira etapa foi da implanta??o da infraestrutura geod?sica de refer?ncia para a realiza??o dos levantamentos geod?sicos da ?rea de estudo. Compreendeu a implanta??o da Rede GPS do Litoral Setentrional do RN (RGLS), constitu?da de esta??es com coordenadas geod?sicas e altitudes ortom?tricas de precis?o; posicionamento de Refer?ncias de N?vel (RN) e avalia??o do modelo geoidal gravim?trico dispon?vel, para serem utilizados na altimetria por GPS de precis?o; e desenvolvimento de aplicativos para a altimetria por GPS de precis?o. A segunda etapa foi do desenvolvimento e aperfei?oamento de metodologias para o levantamento, processamento, representa??o, integra??o e an?lises de Linhas de Costa (LC) e Modelos Digitais de Eleva??o (MDE) obtidos por t?cnicas geod?sicas de posicionamento. Incluiu desde a escolha dos equipamentos e m?todos de posicionamento a serem utilizados, em fun??o da precis?o requerida e da estrutura implantada, at? a defini??o do indicador de LC e dos referenciais geod?sicos mais adequados ao monitoramento costeiro de precis?o. A terceira etapa foi do monitoramento geod?sico sazonal da ?rea de estudo. Definiu as ?pocas de execu??o dos levantamentos geod?sicos, a partir da an?lise do padr?o de din?mica sedimentar da ?rea de estudo; execu??o dos levantamentos, com os objetivos de calcular e localizar ?reas e volumes de eros?o e acres??o (balan?os sedimentares areal e volum?trico) ocorridas nas LC e nas superf?cies das praias e ilhas ao longo do ano, e estudo das correla??es entre as varia??es mensuradas (em ?rea e volume) entre os levantamentos e a atua??o dos agentes din?micos costeiros. Os resultados permitiram um estudo integrado das rela??es espaciais e temporais das causas e consequ?ncias dos intensos processos costeiros atuantes na ?rea, especialmente com a mensura??o da variabilidade da eros?o, transporte, balan?o e suprimento sedimentares ao longo do ciclo anual de constru??o e destrui??o das praias. Nas an?lises dos resultados, foi poss?vel identificar as causas e consequ?ncias da intensa eros?o costeira nas praias expostas, analisar a recupera??o sedimentar das praias e a acres??o nos canais de mar? e nos estu?rios. A partir da ?tica das varia??es sazonais das linhas de costa, interven??es antr?picas de conten??o de eros?o foram propostas com o objetivo de recuperar a situa??o anterior das praias em processo de eros?o.
4

Měření posunů a přetvoření mostu Gagarin / Deformation Measurement of Gagarin Bridge

Czíria, Kornél January 2016 (has links)
The work deals with a complex analysis of displacements and deformations of one bridge span of the railway bridge "Gagarin". The bridge structure was since 2009 annually measured. In addition to long-term monitoring of the bridge a 24-hour automatized monitoring was conducted in 2015 using robotic total station. The results of monitoring enables the analysis of displacements and deformations, analysis of measurement accuracy and also environmental influences on the structure - determination of the temperature dependence of deformations. Another part of the work is evaluating the long-term stability of the height reference frame that was used for geodetic epoch measuring of the bridge columns. The results of the work are the values of detected displacements and deformations, their graphical illustration, geometric interpretation and relevant characteristics of accuracy.
5

Genesis, conservation and deformation of ice-rich mountain permafrost:

Kenner, Robert 30 May 2018 (has links) (PDF)
This thesis analyses ice-rich mountain permafrost with regard to its genesis, distribution, deformation and interaction with other environmental factors. The processes influencing ground ice formation in ice-rich and ice-poor mountain permafrost are highlighted. Factors influencing the presence of ice-rich permafrost are identified and their individual or combined effect on frozen ground is determined. Based on these findings, a new permafrost distribution map of Switzerland was created, which specifies permafrost temperature and ice contents and considers rock glacier creep paths. The deformation of rock glaciers is investigated with newly developed monitoring systems and concepts. This enables a better understanding of the processes leading to rock glacier acceleration at different time scales.
6

Genesis, conservation and deformation of ice-rich mountain permafrost:: Driving factors, mapping and geodetic monitoring

Kenner, Robert 29 January 2018 (has links)
This thesis analyses ice-rich mountain permafrost with regard to its genesis, distribution, deformation and interaction with other environmental factors. The processes influencing ground ice formation in ice-rich and ice-poor mountain permafrost are highlighted. Factors influencing the presence of ice-rich permafrost are identified and their individual or combined effect on frozen ground is determined. Based on these findings, a new permafrost distribution map of Switzerland was created, which specifies permafrost temperature and ice contents and considers rock glacier creep paths. The deformation of rock glaciers is investigated with newly developed monitoring systems and concepts. This enables a better understanding of the processes leading to rock glacier acceleration at different time scales.

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