[en] Convergence measurements were taken during the construction of a circular shaft in massive granite. The convergence results were used to back-calculate the in situ horizontal stress orientation and magnitudes. The results from the convergence method were supported by other measurement techniques and numerical modelling. (author). 16 refs., 1 tab., 10 figs

[en] Using the solution of the problem of elastic half-space's reaction to normal and axial tangent loads, running along circular cavity, we investigate the mode of deflection of rock massif in the vicinity of shallow-placed tunnel under the influence of loads of the above-stated kinds evenly distribution along the tunnel's final length. (author)

[en] Eight constitutive laws that are used to describe the creep of salt and the assumptions implicit in these laws are reviewed. None of the laws have a firm physical basis, but all can adequately reproduce laboratory data obtained under constant stress and temperature. Laboratory experiments having complex thermomechanical histories, however, cannot be simulated nearly as well. A sufficient condition is discussed for the existence of a creep potential required to extend one-dimensional creep laws generated from laboratory data to three-dimensions as needed for structural analyses. This condition cannot be met exactly if creep is controlled by the mechanisms that are thought to be operative in the range of stress and temperature expected in a nuclear waste repository. The exponential-time law is selected as the baseline creep law for use in calculations that are performed to assess the performance of a potential nuclear waste repository. Recommendations are given for determining if the physical basis of the baseline creep law is adequate and for assessing the potential for creep rupture

[en] The Sierra Bermeja Pluton (southern Central Iberian Zone, Iberian Massif) is a late-Variscan intrusive constituted by cordierite-bearing peraluminous monzogranites. Detailed field mapping has allowed to disclose the presence of several NE–SW trending longitudinal composite bodies, formed by either aphanitic or phaneritic mesocratic rocks. According to their petrography and geochemistry these rocks are categorised as calc-alkaline lamprophyres and vaugnerite series rocks. Their primary mineralogy is characterised by variable amounts of plagioclase, amphibole, clinopyroxene, biotite, K-feldspar, quartz and apatite. Broadly, they show low SiO2 content (49–56wt.%), and high MgO+FeOt (10–17wt.%), K2O (3–5wt.%), Ba (963–2095ppm), Sr (401–1149ppm) and Cr (87–330ppm) contents. Field scale observations suggest that vaugneritic rocks and lamprophyres would constitute two independent magma pulses. Vaugneritic dioritoids intruded as syn-plutonic dykes, whereas lamprophyres were emplaced after the almost complete consolidation of the host monzogranites. In this way, vaugnerite series rocks would be an evidence for the contemporaneity of crustal- and mantle-melting processes during a late-Variscan stage, while lamprophyres would represent the ending of this stage.

[en] Rocks exhibit a nonlinear elastic behaviour at low stresses. This is due to the presence of pores and microfractures in the rock. This phenomenon has been studied in the past by a number of investigators. An attempt is being made to utilize this phenomenon in characterizing rocks in terms of the effect that stress has on changes in pore structure and, therefore, radio-nuclide migration. This is being accomplished by polynomial regression of the nonlinear stress-strain curves and the development of nonlinear elastic parameters

[en] This report examines the behaviour of underground openings in discontinuous rock in response to seismic waves associated with either earthquakes or rock bursts. A literature search revealed that well-constructed underground structures, such as would be expected for nuclear fuel waste disposal vaults, underground pumped-storage or nuclear plants, have an extremely high resistance to damage from seismic motion. To complement these qualitative results, it was necessary to examine the basic mechanisms of the entire progression of seismic motion, from wave generation and propagation, to wave interaction with the underground opening. From these investigations, it was found that unless a seismic event occurs very close to the installation, the stresses generated will be low with respect to the excavation stresses, because high stress waves are rapidly attenuated in travelling through rock. As well, an earthquake may generate extremely high accelerations, but is limited in the maximum amount of stress that it can create. The question, however, of the actual specific nature of underground seismic motions still remains essentially unanswered, although it is expected that there is a reduction in peak motions with depth due to the effect of the free surface of the earth

[en] Rock mechanics literature has documented the challenges, failures and successes of tunnelling through weak rocks. Cases usually deal with low RMR rock masses or high stresses in a fractured zone. With the combination of 5 MPa water pressure, 14 RMR ground with clay infillings and ground freeze walls, the case of the 510-8225N development drift at McArthur River is certainly much more challenging, especially when high grade uranium production is at stake. The article explains the excavation and the ground control techniques that were used to overcome the challenges of development at the Unconformity in the Athabasca Basin. (author)

[en] The systematic prospection at Tebalungkang sector, West Kalimantan was carried out to characterize the occurrence of U mineralization and to invent the potential U resources at the area. The investigation was done on the basis of previous results, i.e. radiometric anomalous outcrops and boulders of 1000-7000 C/s. The methods for the investigation was systematic geological mapping and radiometric measurements of soil and tranced rocks and supported by mineralogical and geochemical analyses. The results of the investigation show that this area consists of metamorphic rocks, intruded by granite quartz-diorite batholites and dike of andesite and lamprophyre. From geological structure this is 30^o plunging from anticlin NE-SW and NNW-SSE, is crossed by NE-SW and E-W normal faults and NW-SE and WNW-ESE strike slip faults. Uranium mineralization appears in quartz-schist brecciated and quachitite (lamprophyre). The radioactive minerals were thorite and monazite, associated with rutile, ilmenite, magnetite, hematite, pyrite, calcopyrite, muscovite, apatite and allanite. The U content from rock samples has been found to be 4,5-54,75 ppm U

[en] After a review of the geology of the Gulf Coast salt domes, the geology (geomorphology and tectonics) and hydrology of Avery Island Dome, 10 miles south-southwest of New Iberia, Louisiana, were studied in detail. Rock mechanics were studied using grouts and piezometers. 17 figs

[en] Pacific Northwest Laboratory (PNL) currently supports the US Department of Energy's Office of Civilian Radioactive Waste Management in developing and evaluating analytical methods for assessing the suitability of sites for geologic disposal of high-level radioactive waste. The research includes consideration of hydrological, geomechanical, geochemical, and waste package components and the evaluation of the degree of coupling that can occur between two or more of these components. The PNL effort and those of other research groups investing potential waste sites in the US and abroad are producing a suite of computer codes to analyze the long-term performance of the proposed repository sites. This paper summarizes the ongoing research in rock mechanics at PNL involving flow through jointed rock. The objective of this research is to develop a methodology for modeling the coupled mechanical-hydrological process of flow through joints and then attempt to validate a ''simple'' model using small-scale laboratory test data as a basis for judging whether the approach has merit. This paper discusses the laboratory tests being conducted to develop a joint behavioral constitutive model for the numerical method under development and the modeling approach being considered