[en] The model presented in this paper is an adaptation of a model developed at the LaEGO for modelling poro-mechanical behaviour of argilites type rocks, allowing to account for anisotropy. (authors)

[en] This paper presents the results of a laboratory testing program that was designed to investigate the mechanical behaviour of the Tournemire argillite. Eighty rock samples were obtained from boreholes drilled at different angles in the walls and floor of an existing gallery at the Tournemire Underground Research Laboratory (URL), France. The experimental program consists of the measurement of the physical properties of the argillite and its mechanical response to loading during uniaxial tests, triaxial tests with various confining pressures, unconfined and confined cyclic tests, and Brazilian tests. Since the Tournemire argillite is characterized by the presence of closely spaced bedding planes, the rock specimens were loaded in different directions to bedding planes (i.e., loading orientation angle, θ = 0^o, 30^o, 45^o, 60^o, and 90^o). Acoustic emission data were also recorded to detect the initiation and propagation of micro-cracks during the uniaxial tests. Most of the tests were performed at the natural moisture content of the rock specimens as delivered to CANMET Laboratories in Ottawa, Canada, where the experiments were conducted. The main objective of the testing program is to identify the mechanical properties of the Tournemire argillite. This paper mainly focuses on the description and interpretation of the test results. The development of an elastoplastic-damage model to describe the mechanical behaviour of the Tournemire argillite is the subject of another paper. (author)

[en] This paper describes the application of CLoE model to an argillite. A main advantage of this constitutive equation is a realistic modeling of failure. It is a clear experimental result that rupture of geo-materials either in laboratory tests or in the field is localized. CLoE models are explicitly based on localized rupture and some parameter involving an induced anisotropy is used to fit experimental rupture data. This paper is an application of the model to an argillite in order to identify the corresponding parameter. The experimental data have been done in another laboratory. This work is more a presentation of a way of thinking geo-material modeling illustrated by a calibration starting from experimental data, than a paper about models aimed at proving that the model is satisfactory. (author)

[en] Hyper-enriched black shale (HEBS) deposits in northern Yukon, consist of thin (<10 cm), laterally extensive (tens of thousands of km²) stratiform sulfide mineralization layer(s) that are hyper-enriched in Ni, Mo, Zn, platinum group elements, Re, and Au. The genesis of HEBS deposits and the ambient paleoenvironment in which they formed are the subject of vigorous debate. Non-traditional stable isotopes, particularly molybdenum and thallium, are robust paleoredox indicators and we have employed these isotope systems in this study of Yukon HEBS. Systematic sampling and Mo and Tl isotopic analysis of a continuous 200 m stratigraphic section through the Yukon HEBS mineralization and footwall and hanging-wall strata at the Peel River north and south bank showings (spaced five km apart) give δ⁹⁸Mo –1.24 to –0.53‰ and –8.1 to –5.2 ε-units for the mineralization and –0.70 to 0.60‰ and –6.5 to –2.0 ε-units for the unmineralized strata. These values preclude a hydrothermal origin and strongly suggest that redox processes were responsible for the Yukon HEBS mineralization. The isotopic compositions, together with rare earth element (REE) systematics (REE profile, Y positive anomalies, Ce negative anomalies, and Y/Ho values) and other bulk geochemical redox indicators (Mo, V, Re/Mo, Ni/Co, U/Th, and V/Cr) indicate that the Peel River HEBS mineralization formed because of metal scavenging from seawater in a quiescent, euxinic basinal paleoenvironment. (author)

[en] We discuss the computational aspects of a porous flow past a reacting solid undergoing pyrolysis. We present governing equations and develop an accurate numerical method for their solution. The algorithm accurately calculates the rapidly varying component and uses a fixed step size commensurate with the smoothly varying component of the solution. The resulting nonlinear equation is solved with Newton's method; the linear system is solved using a discrete analog of the invariant-imbedding method for second-order, linear, two-point boundary-value problems. We also develop a criterion for truncating the computational domain to minimize the calculational effort, and we present some typical calculations showing that the scheme is accurate and efficient

[en] Here we detail the new data acquisition system (DAS) developed for the CSIRO Nuclear Microprobe primarily to handle large detector arrays and to work in tandem with the Maia detector system. Both systems use HYMOD FPGA-based processors. The current DAQ system and its microscopy suite and beam handling have been integrated with the HYMOD system(s) to facilitate easy access to the either system. Examples of the new scanning modes available with the combined system are highlighted on a complex Cambrian black shale sample from the Yangtze basin in Southern China.

No abstract available

[en] Highlights: • The influence of ScCO₂ adsorption on the failure behavior of shale is investigated. • Properties considered: BSS, E, U, and fracture trace. • ScCO₂ adsorption for 60 days was observed to reduce BSS by 46%, E by 22%, and U by 50%. • Fragmentation is the root cause of deterioration in the mechanical properties of shale. -- Abstract: This paper investigates variation in the failure behavior of shale in a ScCO₂-immersion environment with different adsorption periods and layering orientations. Eight types of specimens are investigated, where the inclination of the layering to the applied force θ is 0°, 15°, 30°, 45°, 60°, 75°, 90°, and Divider type. The period of immersion ranges up to 60 days. The results indicate that after 60 days of ScCO₂ adsorption, the Brazilian splitting strength (BSS), splitting modulus (E) and absorbed energy (U) of the shale were reduced by 46%, 22% and 50%, respectively, versus those of samples in which there was no adsorption. The root cause of this mechanical weakening is that damage done to the shale by ScCO₂ results in the formation of a fragmented structure. Not only tensile failure but also shear failure occurs, making the failure mixed-mode. The mechanical properties of shale show clear changes with θ. Samples with no adsorption, 10-day adsorption, 30-day adsorption and 60-day adsorption show basically consistent change trends with inclination angle (θ).

[en] The quantity of gas and the gas pressure resulting from a nuclear explosion in oil shale is estimated. These estimates are based on the thermal history of the rock during and after the explosion and the amount of gas that oil shale releases when heated. It is estimated that for oil shale containing less than a few percent of kerogen the gas pressure will be lower than the hydrostatic pressure. A field program to determine the effects of nuclear explosions in rocks that simulate the unique features of oil shale is recommended. (U.S.)

[en] Document available in extended abstract form only. Fluid pressure or hydraulic head measured in wells in geological formations can respond to Earth tidal forces and atmospheric pressure variations. At Andra Meuse/Haute-Marne underground research laboratory located in Bure (France), water level and fluid pressure are measured in several boreholes in the Callovo-Oxfordian clay formation (COX) and in overlying geological formations. One of these boreholes (EST207) is equipped with a multi-packer system monitoring 11 intervals, including 8 in the COX. The recorded fluid pressures in EST207 were analyzed to determine possible Earth tidal responses. In this borehole, the fluid pressure and atmospheric pressure variations data are recorded every fifteen minutes and 6.5 years of such data from 2004/06/02 to 2010/12/31 were analyzed. Various perturbed data, gaps, drift and abnormal data were corrected through a data preprocessing process. Data interpolation and filtering processes were performed to have data available every 15 minutes at 0, 15, 30 and 45 minutes on the hour. A spectral analysis (Fast Fourier Transform) of each pressure data series shows amplitude peaks at frequencies corresponding to various Earth tidal frequencies: diurnal and semi diurnal waves can be identified. Spectral analyses were also performed on the atmospheric pressure data. The solar semi diurnal wave (S2) was identified. The 'Earth Tides ETERNA package' was used to separate the waves according to the frequencies bands. The analyses performed using ETERNA are indicated as 'Earth Tidal Analyses' (ETAN). Tidal parameters are estimated from ETAN: amplitudes A and its standard deviation σ(A)[hPa], phase φ for the main waves in diurnal and semi diurnal frequencies bands before and after atmospheric pressure variations correction. The barometric efficiency (BE) and its standard deviation σ (BE) as regression coefficient is calculated. The atmospheric pressure data are also analyzed with ETERNA; the wave S2 amplitude and phase values usually taken into account as references are in good agreement with values calculated at others sites. This result validates the atmospheric pressure data sets. Having high quality data and multi-year data sets, it was possible to separate several main tidal waves in the diurnal band and in the semi diurnal band. K1, O1, P1, S1 and M2, N2, S2, K2 bands were first taken into account in each series to determine whether they were significant or not. The ETAN results are in good agreement with the spectral analyses results and with these results it can be concluded that the 11 monitoring intervals in borehole EST207 respond to Earth Tidal forces and to atmospheric pressure variations. The ETERNA software allows identifying more tidal waves with more accuracy. In all the intervals, the best identified significant waves are O1, K1, M2 and S2. While the M2 amplitude is not or only slightly perturbed by atmospheric pressure variations and the M2 phase is not, the S2 wave amplitude and phase are very sensitive to atmospheric pressure. After barometric correction, the amplitudes through the borehole are generally decreasing from the bottom to the top. In a preliminary hydrogeological interpretation, the detailed intercomparison of tidal analyses results according to the barometric correction effect, the BE values and the waves identification quality provide a classification of the barometric and tidal responses as a function of the various intervals. These responses were classified into four groups depending on the monitoring intervals in the Dogger, the lower COX, the upper COX and the base of Oxfordian. The BE values show that the greater the clay content of the formation is, the greater the BE values are. The BE values in the Dogger are similar to the values estimated in the Oxfordian. In 2003, Andra investigated earth tides and barometric responses in the Oxfordian of two boreholes, EST203 and EST104. The hydrogeological interpretation in these two boreholes provided estimates of transmissivity and storage coefficient consistent with the pump tests results. In fact Earth tidal and barometric responses in wells can be used to estimate hydrogeological parameters effectively without classical pump test experiments and over a long time period. In the eleven intervals in borehole EST207 and particularly in the COX, the Earth tidal and barometric responses are dependent on the formation geology and the hydrogeological parameters. Preliminary interpretation to derive certain hydrogeological parameters of the COX could be refined. These parameters could be estimated by analyzing the tidal parameters and barometric responses combined with a tidal dilatation model. This tidal dilatation model could also be obtained from measurements of three directional extensometers with suitable equipment. (authors)