Synopsis The present Paper describes a procedure for estimating the danger of a base failure in a strutted excavation in clay. Terzaghi and Tschebotarioff have previously given formulae for such calculations, but these are limited to shallow excavations. On the basis of the familiar bearing capacity calculations for foundations on clay a new approach to the problem is developed, in which the critical depth of an excavation is given by: where s and y are the undrained shear strength and density of the clay, respectively. Nc is a dimensionless coefficient depending on the form of the excavation, i.e., the width/length ratio and the depth/width ratio. The values of Nc are identical to those given by Skempton (1951) for bearing capacity formulae. The reliability of the formula is indicated by comparisons with fourteen excavations. In seven of these excavations complete failure occurred, the theoretical safety factor having an average of 0·96. In four excavations a partial failure was obtained, with an average theoretical safety factor of 1·11. The last three excavations were successfully performed, but site observation indicated that, with further depth, danger of failure would be serious. These excavations had an average theoretical safety factor of 1·08. These investigations therefore indicate that the danger of base failure in excavations in clay may be estimated from the above theoretical approach with sufficient accuracy for most practical purposes. L'article suivant donne une description de la méthode théorique pour la calculation du danger d'un soulèvement du fond d'une fouille cadragée dans l'argile. Terzaghi et Tschebotarioff ont déjà donné des formules pour un calcul pareil. mais ces formules ne sont valables que pour des fouilles de petite profondeur Basée sur les formules de la capacité portante des fondations dans l'argile, une nouvelle solution du problème de soulèvement du fond a été développée. La profondeur critique d'une fouille est donée par: où s et y sont respectivement la résistance au cisaillement et le poids d'unite de I'argile. Nc étant un coefficient sans dimensions et dependant de la forme de la fouille, c'est-à-dire de la proportion largeur-longueur et de la proportion profondeur-largeur. Les valeurs de Nc, identiques aux valeurs données par Skempton (1951) pour la capacité portante, sont montrées graphiquement dans la Figure 2. La validité de ces formules a été: examinée par comparaison de quatorze fouilles. Dans sept de ces fouilles, un soulévement total du fond a eu lieu, les coefficients théoriques de sécurité donnant comme valeur moyenne de 0,96. Quatre fouilles, où on constatait un soulévement partiel du fond, ont fourni une valeur moyenne des coefficients théoriques de sécurité de 1·ll. Les trois dernières fouilles ont été accomplies sans évènements spéciaux, mais des observations sur place indiquaient que, avec une profondeur agrandissante, on aurait dû craindre un soulevement du fond, la valeur moyenne des coefficients théoriques de sécurité étant de 1,08. Les résultats obtenus ci-dessus montrent, ainsi, que la méthode dérite nous permet d'estimer avec une précision suffisante le danger d'un soulevement du fond d'une fouille dans I'argile, et que la méthode suffit pour la plupart des usages pratiques.

The poor rock quality and matrix permeability several orders of magnitude lower than conventional oil reservoirs observed in unconventional liquid reservoirs (ULR) presents many uncertainties on the storage capacity of the rock and the possibility of enhancing recovery. The technological advances in multiple stage hydraulic fracturing and horizontal drilling have improved the overall profitability of oil shale plays by enhancing the matrix -wellbore connectivity. The combination of these technologies has become the key factor for the operators to reach economically attractive production rates in the exploitation of ULR, causing a lot of focus on their improvement. However, as the reservoir matures, primary production mechanisms no longer drive oil to the hydraulic fractures, making the improvement of matrix -wellbore connectivity insufficient to provide economically attractive production rates. Therefore, the need to develop enhanced recovery techniques in order to improve the displacement of the oil from the matrix, maintain profitable production rates, extend the life of the assets and increase ultimate oil recovery becomes evident.This study presents experimental results on the use of CO 2 as an enhanced oil recovery (EOR) agent in preserved, rotary sidewall reservoir core samples with negligible permeability. To simulate the presence of hydraulic fractures, the ULR cores were surrounded by high permeability glass beads and packed in a core holder. The high permeability media was then saturated with CO 2 at constant pressure and temperature during the experiment. Production was monitored and the experiment was imaged using x-ray computed tomography to track saturation changes inside the core samples.The results of this investigation support CO 2 as a promising EOR agent for ULR. Oil recovery was estimated to be between 18 to 55% of OOIP. We provide a detailed description of the experimental set up and procedures. The analysis of the x-ray computed tomography images revealed saturation changes within the ULR core as a result of CO 2 injection. A discussion about the mechanisms is presented, including diffusion and reduction in capillary forces. This paper opens a door to the investigation of CO 2 enhanced oil recovery in ULR.

This work demonstrates that diffusion may be a viable oil-recovery mechanism in fractured reservoirs during injection of carbon dioxide (CO 2 ) for enhanced oil recovery, depending on the CO 2 distribution within the fracture network and distance between fractures. High oil recovery was observed during miscible, supercritical CO 2 injection (R F ¼ 86% original oil in place) in the laboratory with a fractured chalk core plug with a large permeability contrast. Dynamic 3D fluid saturations from computed-tomography (CT) imaging made it possible to study the local oil displacement in the vicinity of the fracture, and to calculate an effective diffusion coefficient with analytical methods. The obtained diffusion coefficient varies between 0.83 and 1.2 Â10 À9 m 2 =s, depending on the method used for calculation. A numerical sensitivity analysis, with a validated numerical model that reproduced the experiments, showed that the rate of oil production during CO 2 injection declined exponentially with increasing diffusion lengths from the CO 2 -filled fracture and oil-filled matrix. In a numerical upscaling effort, with the experimentally achieved diffusion coefficient, oilrecovery rates and local flow were studied in an inverted five-spot pattern in a heavily fractured carbonate reservoir.

CRMgeo is a formal ontology intended to be used as a global schema for integrating spatiotemporal properties of temporal entities and persistent items. Its primary purpose is to provide a schema consistent with the CIDOC CRM to integrate geoinformation using the conceptualizations, formal definitions, encoding standards and topological relations defined by the Open Geospatial Consortium in GeoSPARQL. To build the ontology, the same ontology engineering methodology was used as in the CIDOC CRM. CRMgeo first introduced the concept of Spacetime volume that was subsequently included in the CIDOC CRM and provides a differentiation between phenomenal and declarative Spacetime volume, Place and Time-Span. Phenomenal classes derive their identity from real world phenomena like events or things and declarative classes derive their identity from human declarations like dates or coordinates. This differentiation is an essential conceptual background to link CIDOC CRM to the classes, topological relations and encodings provided by Geo-SPARQL and thus allowing Lehrstuhl für Digital Humanities, Universität Passau, Passau, Germany spatiotemporal analysis offered by geoinformation systems based on the semantic distinctions of the CIDOC CRM. CRMgeo introduces the classes and relations necessary to model the spatiotemporal properties of real world phenomena and their topological and semantic relations to spatiotemporal information about these phenomena that was derived from historic sources, maps, observations or measurements. It is able to model the full chain of approximating and finding again a phenomenal place, like the actual site of a ship wreck, by a declarative place, like a mark on a sea chart.

It is still a big technical problem to establish a relation between a shape and its meaning in a sustainable way. We present a solution with a markup method that allows for labeling parts of a 3D object very much like labeling parts of a hypertext. A 3D markup can serve both as hyperlink and as link anchor, which is the key to bidirectional linking between 3D objects and Web documents. Our focus is on a sustainable 3D software infrastructure for application scenarios ranging from email and Internet over authoring and browsing semantic networks to interactive museum presentations. We demonstrate the workflow and the effectiveness of our tools by redoing the Arrigo 3D Showcase. We are working towards a best practice example for information modeling in cultural heritage.