The surface roughness of unfilled rock discontinuities has a major influence on the hydro-mechanical behaviour of discontinuous rock masses. Although it is widely recognized that surface roughness is comprised of large-scale (waviness) and small-scale (unevenness) components, most investigations of surface roughness have been restricted to small fracture surfaces (<1m2). Hence, the large-scale components of roughness are often neglected. Furthermore, these investigations typically define roughness using two-dimensional profiles rather than three-dimensional surfaces, which can lead to biased estimates of roughness. These limitations have led to some contradictory findings regarding roughness scale effects. This thesis aims to resolve some of these issues. The main findings indicate that discontinuity roughness increases as a function of the sampling window size contrary to what is commonly assumed. More importantly, it is shown that the estimated roughness significantly decreases as the resolution of surface measurements decrease, which could lead to the under estimations of roughness and, consequently, discontinuity shear strength.

Thesis (M.S)--University of Tennessee, Knoxville, 2002. / Title from title page screen (viewed on Feb. 26, 2003). Thesis advisor: Eric C. Drumm. Document formatted into pages (viii, 76 p. : ill. (some col.), maps). Vita. Includes bibliographical references.

published_or_final_version / Applied Geosciences / Master / Master of Science

Not available / text

Not available / text

Not available / text

No description available.

Στα πλαίσια της παρούσας διπλωματικής εργασίας εκτελέστηκαν δοκιμές εντός του εργαστηρίου σε δοκίμια βραχωδών σχηματισμών. Η εργασία εστιάζει σε δύο περιοχές εντός του Ελλαδικού χώρου, στα Μέθανα και στο Καλλίδρομο. Τα πετρώματα της περιοχής των Μεθάνων αντιστοιχούν σε ανδεσίτες και δακίτες, ενώ εκείνα του Καλλιδρόμου αντιστοιχούν σε περιδοτίτες. Βασικός σκοπός ήταν η μελέτη και ο καθορισμός των τεχνικογεωλογικών χαρακτηριστικών των πετρωμάτων από τις δύο προαναφερθείσες περιοχές. Προς την κατεύθυνση αυτή, έγιναν δοκιμές με στόχο τη διερεύνηση των φυσικών, δυναμικών και μηχανικών χαρακτηριστικών τους καθώς και συσχετίσεις μεταξύ τους. / --

No description available.

An investigation was conducted as a preliminary effort to develop a methodology to predict pore pressure in a rock formation during drilling, for all types of rocks and situations. Specifically, it was investigated whether or not the virgin pore pressure (the pore pressure of the undisturbed rock) can be determined at the drill bit from drilling and environmental parameters, as well as solid and pore fluid properties. Several drilling situations were analyzed to develop models relating pore pressure to drilling and environmental parameters, as well as solid and pore fluid properties. Three approaches to the modeling of such drilling situations were considered, which were used to predict pore pressure and compare the predictions to actual drilling data. The first approach used the concept of the effective stress in conjunction to the Mohr-Coulomb failure criterion. The second approach used the concept of the mechanical specific energy. The third approach made use of basic principles to relating virgin pore pressure to drilling and environmental parameters, as well as solid and pore fluid properties. This third approach resulted in the proposal of a more fundamental way of viewing mechanical specific energy (MSE) and the use of Biot's poroelasticity theory to describe the cutting process of rock. The first approach did not provide an adequate prediction of virgin pore pressure for all types of rocks and situations. The second approach showed promising results with limited actual drilling data. A sensitivity analysis of the model resulting from the third approach indicated that pore pressure, type of rock, and back rake angle of the cutter are the most significant factors affecting the energy required to break the rock. Moreover, rate of cutting stress, depth of cut, and type of pore fluid become significant factors of the cutting process only when a low-porosity, low-permeability rock is considered. It was concluded that there exists a relationship among pore pressure, drilling and environmental parameters, as well as solid and pore fluid properties. Therefore, it is possible in principle to determine the virgin pore pressure at the drill bit from drilling parameters, environmental parameters, and material properties. However, further work is required to establish a quantitative relationship among the significant parameters before a methodology to predict virgin pore pressure for all types of rocks and situations can be developed.