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1	Assessing the Transient Flow Behavior in Falling-head Permeameter Tests Cavdar, Sevgi 03 October 2013 (has links) The proportionality constant in Darcy's Law is called hydraulic conductivity (K), and it is the most fundamental parameter to groundwater studies. There are a number of in situ and laboratory techniques employed to determine K, one of which is falling head permeameter (FHP). In FHP, determining K involves two steps: measuring hydraulic head change over time and calculating the K value. In the past, calculating K was done using Darcy's Law, which states linear correlation between the flux and the hydraulic gradient, but this is only true when the inertial forces are negligible at small velocities. At higher velocities, flow becomes unsteady because of the change over time in flow magnitude and hydraulic gradient, which requires mass conservation law to be combined with Darcy’s Law and eventually leads to Laplace’s equation for an incompressible matrix. If the media is compressible, specific storativity should be taken into account, as well. In this study, we investigated the transiency of flow in FHP tests by analyzing the effect of specific storativity on K calculations. We have developed a new semi- analytical solution for transient flow in FHP in Laplace domain and used the de Hoog algorithm to attain the inverse Laplace transform of this solution to yield solutions in time domain. We have also provided some analysis and a comparison of steady-state solution along with using experimental data and the data from the literature to analyze the solution. Upon these, we concluded that the transient flow in falling-head tests has minimal effect in general, although using the transient solution provided may improve the accuracy without a major effect. storativity specific storativity falling-head permeameter transient
2	Méthodologie d’analyse des signaux et caractérisation hydrogéologique : application aux chroniques de données obtenues aux laboratoires souterrains du Mont Terri, Tournemire et Meuse/Haute-Marne / Signal analyzis methodology and hydrogeologic characterization : application to time series collected at the underground research laboratories of Mont Terri, Tournemire, and Meuse/Haute-Marne Fatmi, Hassane 29 May 2009 (has links) Ce rapport présente des méthodes de prétraitement, d'analyse statistique et d'interprétation de chroniques hydrogéologiques de massifs peu perméables (argilites) dans le cadre d'études sur le stockage profond de déchets radioactifs. Les séries temporelles analysées sont la pression interstitielle et la pression atmosphérique, en relation avec différents phénomènes (marées terrestres, effet barométrique, évolution de l'excavation des galeries). Les pré-traitements permettent de reconstituer et homogénéiser les chroniques de données en présence de lacunes, aberrations, et pas de temps variables. Les signaux prétraités sont ensuite analysés en vue de caractériser les propriétés hydrauliques du massif peu perméable (emmagasinement spécifique ; porosité effective). Pour cela, on a développé et mis en oeuvre les méthodes d'analyses suivantes (implémentées en Matlab): analyses corrélatoires et spectrales (Fourier) ; analyses ondelettes multirésolution ; enveloppes de signaux aléatoires. Cette méthodologie est appliquée aux données acquises au Laboratoire Souterrain du Consortium International du Mont Terri (Jura Suisse), ainsi qu'à certaines données des Laboratoires Souterrains de Tournemire (Aveyron) et de Meuse / Haute-Marne (ANDRA) / This report presents a set of statistical methods for pre-processing and analyzing multivariate hydrogeologic time series, such as pore pressure and its relation to atmospheric pressure. The goal is to study the hydrogeologic characteristics of low permeability geologic formations (argilite) in the context of deep disposal of radioactive waste. The pressure time series are analyzed in relation with different phenomena, such as earth tides, barometric effects, and the evolution of excavated galleries. The pre-processing is necessary for reconstituting and homogenizing the time series in the presence of data gaps, outliers, and variable time steps. The preprocessed signals are then analyzed with a view to characterizing the hydraulic properties of this type of low permeability formation (specific storativity; effective porosity). For this sake, we have developed and used the following methods (implemented in Matlab): temporal correlation analyses; spectral/Fourier analyses; multiresolution wavelet analyses envelopes of random processes. This methodology is applied to data collected at the URL (Underground Research Laboratory) of the Mont Terri International Consortium (Swiss Jura), as well as some other data collected at the URL of IRSN at Tournemire (Aveyron) and at the URL of ANDRA (Meuse / Haute-Marne) Mont Terri Tournemire Bure Argilite Argiles à Opalines Callovo-Oxfordien Pression interstitielle Chroniques Séries temporelles Traitement des signaux Processus aléatoires Prétraitements Reconstitution Analyse corrélatoire Analyse spectrale Ondelettes multirésolution Marées terrestres Effet barométrique Compressibilité Porosité Emmagasinement spécifique Porosité effective EDZ (Excavation Damaged Zone) Perméabilité Pore pressure Argilite Signal pre-processing Random processes Earth tides Barometric effect Specific storativity Effective porosity Correlation analyses Spectral Fourier analyses Multiresolution wavelet analyses EDZ (Excavation Damaged Zone) Hydrogeology

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Assessing the Transient Flow Behavior in Falling-head Permeameter Tests