Συσχέτιση φυσικομηχανικών ιδιοτήτων με δομικά
χαρακτηριστικά τεκτονισμένων ασβεστόλιθων

Μαζιώτη, Νεφέλη-Ζωή; Mazioti, Nefeli-Zoi

dc.contributor.author	Μαζιώτη, Νεφέλη-Ζωή	el
dc.contributor.author	Mazioti, Nefeli-Zoi	en
dc.date.accessioned	2022-11-29T10:21:34Z
dc.date.available	2022-11-29T10:21:34Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/56293
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.23991
dc.rights	Default License
dc.subject	Τεκτονισμός	el
dc.subject	Σσβεστόλιθος	el
dc.subject	Image processing	en
dc.subject	Image segmentation	en
dc.subject	Φυσικομηχανικές ιδιότητες	el
dc.subject	Δομικά χαρακτηριστικά	el
dc.subject	3D reconstruction models	en
dc.subject	Cracking degree	en
dc.subject	Βαθμός ρωγμάτωσης	el
dc.subject	Structural geomaterial quantification	en
dc.title	Συσχέτιση φυσικομηχανικών ιδιοτήτων με δομικά χαρακτηριστικά τεκτονισμένων ασβεστόλιθων	el
heal.type	bachelorThesis
heal.secondaryTitle	Correlation of physical-mechanical properties with the structural characteristics of tectonized limestones	en
heal.classification	Βραχομηχανική	el
heal.language	el
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2022-03-17
heal.abstract	Tectonized rocks are complex rock formations, with reduced mechanical characteristics compared to the intact rock. It has been observed that many of these geomaterials consist of a mixture of rock fragments, called blocks, bonded together with a matrix. Their main attribute is that their overall behavior is usually controlled by the mechanical characteristics of their strongest component, i.e. the rock fragments. However, in cases where the matrix occupies the largest percentage of the geomaterial and the blocks are smaller in size, the opposite occurs. It is also important to take into account the secondary cracks that may exist in such rock formations, as their behavior may also be influenced by them. The geomaterial studied in this Diploma Thesis is tectonized limestone, from three areas of Lefkada island (Greece), which is found in situ as: a) blocks of limestone welded with matrix, b) limestone blocks with no matrix and c) only matrix - the blocks are very small in size and are indistinguishable from the matrix. The scope of this study is to examine the correlation of the geomaterial’s physical-mechanical properties with its structural characteristics, as quantified in terms of the percentage of blocks and matrix, as well as of cracks. The investigated areas are Egremni, whose specimens are examined for the ratio of blocks and matrix, Apolpaina, whose specimens are examined for the quantification of their degree of cracking and Pefkoulia, whose specimens are examined for both aforementioned structural features. Before the present study, laboratory tests were performed on these specimens to determine their physical and mechanical properties. For the quantification of the structural features, an appropriate software was first utilized for the three-dimensional simulation of the specimens, resulting in calibrated orthophotos of all sides. Then, by image analysis, the processed orthophotos were converted into digital binary images, in which the areas covered by matrix in one case and cracks in the other, were visibly separated, in order to be entered into the developed algorithms for the calculation of the proportions of the structure - composition indices. The basic developed algorithms were two, one for the quantification of the blocks and the matrix of the specimens, that exports results in terms of percentages of each structural element for each specimen side, and one for the calculation of the degree of cracking of the specimens. Overall, the correlations of physical-mechanical properties to structural characteristics are quite satisfactory. For the samples from Egremni, there is a good correlation of uniaxial compressive strength to the percentage of matrix, a strength value that reduces with the reduction of the sample blocks. The overall estimate that the material is controlled by the element (block or matrix) having the highest mechanical properties is confirmed. There is also an10 indication that there is a threshold value for the matrix percentage (equal to 40%), which when exceeded, the overall uniaxial compressive strength of the geomaterial remains constant. Thus, when the matrix percentage is higher than 40%, the uniaxial compressive strength is equal to that of the matrix. For the specimens from Pefkoulia, there is a good correlation between the uniaxial compressive strength and the matrix percentage, with this being opposite to that for the specimens from Egremni, i.e., here an increase in the matrix percentage leads to an increase in uniaxial compressive strength. This is due to the fact that the matrix of these specimens has better mechanical properties than the rock fragments and hence, it prevails. As the available specimens belong to a limited range of matrix percentage values (50% - 76%), they cannot be considered as a representative sample of the total geomaterial in the area, thus more data are required for a complete comprehension. The cracking indices of the specimens from Pefkoulia have a fairly constant ratio with each other and seem very representative of the state of the geomaterial in situ. However, they have a moderate degree of correlation with the uniaxial compressive strength of the geomaterial. Therefore, the simultaneous influence of the matrix percentage and the cracking indices was evaluated, through a multivariable regression model, which also improved the simple correlation between the matrix percentage and the uniaxial compressive strength. Consequently, the behavior of this geomaterial is controlled partly by the simultaneous existence of cracks. Finally, for the specimens from Apolpaina, which consist of a different geomaterial from the other two areas (without the presence of a mixture of fragments and matrix), a very good correlation is observed between the indices of degree of cracking, as well as between these indices and the uniaxial compressive strength. The behavior of these specimens is controlled by the degree to which they are cracked, since they are less complex geomaterials than those of the other two areas.	el
heal.advisorName	Παπαδημητρίου, Αχιλλέας	el
heal.advisorName	Σαρόγλου, Χαράλαμπος	el
heal.committeeMemberName	Μαρίνος, Βασίλειος	el
heal.committeeMemberName	Παπαδημητρίου, Αχιλλέας	el
heal.committeeMemberName	Γερόλυμος, Νικόλαος	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Πολιτικών Μηχανικών. Τομέας Γεωτεχνικής	el
heal.academicPublisherID	ntua
heal.numberOfPages	186 σ.	el
heal.fullTextAvailability	false