Variability and anisotropy of mechanical properties of the pittsburgh coal seam     

N. E. Cook Jr.  H. -Y. Ko  K. H. Gerstle 《Rock Mechanics and Rock Engineering》1978,11(1):3-18

SummaryVariability and Anisotropy of Mechanical Properties of the Pittsburgh Coal Seam Results of an experimental program to determine the vertical variation of material stiffness and strength of an important coal seam are presented, with the aim of providing information for realistic modeling for purposes of analysis. The seam is divided into four zones, and data from each are evaluated statistically. It is concluded that this seam contains two zones with measurably different properties, which, however, are small compared to the observed scatter of data.

---

ZusammenfassungStreubereich und Anisotropie der mechanischen Eigenschaften des Pittsburgher Kohleflözes Es werden Ergebnisse eines Versuchsprogramms zur Bestimmung der senkrechten Veränderung der Steifheit und Festigkeit des Materials in einem wichtigen amerikanischen Kohlenflöz präsentiert, um Unterlagen für realistische Modellbildung zum Zwecke der Spannungsberechnung zu liefern. Der Flöz ist in vier Zonen unterteilt, deren Daten statistisch untersucht wurden. Es ergab sich, daß dieser Flöz zwei Zonen mit meßbar unterschiedlichen Eigenschaften enthält; diese Unterschiede sind aber klein im Vergleich zur Streuung der einzelnen Daten.

---

RésuméVariabilité et anisotropie des propriétés mécaniques du banc de charbon de Pittsburgh On a analysé, par échantillons, la variabilité de la résistance et du module d'un banc de charbon épais, avec la profondeur. Le but de l'étude est d'obtenir des valeurs réalistes qui puissent être utilisées dans une analyse par méthodes numériques. Le banc est divisé en quatre zones, et les résultats sont analysés de façon statistique, séparément pour chaque zone. On a conclut que ce banc contient deux zones dont les propriétés mécaniques diffèrent. Cependant ces différences ne dépassent pas l'ordre de grandeur des écarts dans les observations sur chaque zone.

---

---

With 10 Figures  相似文献   

Determination of source and palaeoclimate from the comparison of grain and clay fractions in sandstones: A case study     

Gürol Ataman  Sungu L. Gökçen 《Sedimentary Geology》1975,13(2):81-107

The Paleogene Ke?an Formation of southwestern Turkish Thrace (Alpine Ergene basin) which is dominantly a sandy facies, comprises the Çinarlidere (Lower) and ?aplidere (Upper) members. The turbidite sandstones of the Formation are petrologically defined as multicycle, moderately sorted, angular to subrounded, coarse-skewed, submature graywackes with a detrital clayey matrix of over 15%.The quantitative analyses of light, heavy and clay fractions of sandstone samples from the Ke?an Formation showed marked petrographic variations with grouping of these sediments as Lower- and Upper-member mineralogical facies and led to the following conclusions: a southern terrain with a relatively warm and tropical climate on a terrestrial source of a peneplain topography provided detrital material for the Lower-member sediments (the Biga Massif), while the Upper-member sediments were derived from a rapid erosion of an area of high relief with a uniform supply and continuous infilling of the basin of deposition (a western source terrain: the Rhodope Massif).  相似文献   

Relations entre les données isotopiques océaniques et l'histoire des grandes faunes européennes plio-pleistocenes     

Marie-Françoise Bonifay 《Quaternary Research》1980,14(2):251-262

This study is the first test of correlation between the results obtained on the large Plio-Pleistocene European faunas and the main climatic stages (cold as well as temperate) demonstrated in marine isotopic records. In particular, there are cold stages which often explain the disappearance of some species, as well as climatic events that promote the substitution of some species by other groups. A rather evident parallelism appears between the European succession of large faunal associations and paleoclimatic stages revealed in oceanic areas, but some discordance occurs in the later periods. Faced with the great diversification of the Quaternary faunas, probably due to the multiplicity of climatic environments, and with global information from oceanic records, only local biostratigraphic studies will allow precise reconstruction of the different biotopes.  相似文献   

Twenty Years Seismic Monitoring of Induced Seismicity in Northern Albania     

B. Muço 《Pure and Applied Geophysics》1998,153(1):151-162

—The northern part of Albania has been the focus of an intense effort by the Seismological Institute of Albania, for in this area two of the country’s biggest reservoirs are located. Three years before the impounding of the Fierza reservoir, a four-station network was installed around it. The possibility of induced seismicity continued after the impoundment of the Fierza reservoir in 1978 and the Komani reservoir, in 1985. The seismicity of the zone and some aspects of induced seismicity including temporal correlation of seismicity with water level changes, spatial patterns in seismicity, frequency-mag nitude relations, fault plane solutions etc., are studied during this period. The presence in this zone of a very important transverse fault, the Shkoder-Peja fault, makes the study of induced seismicity from Fierza and Komani reservoirs even more significant. The studies have shown that the impounding of the Fierza and Komani reservoirs has modified the natural course of microearthquake energy release, increasing the number of swarms in this area.¶The fluctuation of the water level in these two reservoirs, in due course, is a potentially important factor in the evaluation of seismicity for Northern Albania and especially in the hazard assessment of this region.  相似文献   

Secondary vorticity centres as centres of secondary (streamwise) vorticity     

Pavla Kočíková  Reviewer O. Zikmunda 《Studia Geophysica et Geodaetica》1977,21(2):185-194

Summary The theory of secondary vorticity is used to explain the essence of so-called secondary or upper vorticity centres, discovered on satellite photographs. The general equation of vorticity, which is then adjusted by means of the equations of state and motion, is transformed into a specially selected intrinsic co-ordinate system. Three-component equations of vorticity are discussed for cases important meteorologically. The conclusion could be drawn that the secondary vorticity centres may be identified with centres of so-called secondary vorticity and that the theoretical facts about their origin and occurrence may be used, together with satellite photographs, to improve weather forecasts.  相似文献   

Production of radionuclides by cosmic rays at mountain altitudes     

Yuji Yokoyama  Jean-Louis Reyss  François Guichard 《Earth and Planetary Science Letters》1977,36(1):44-50

Production rates of²²Na (T_1/2 = 2.6years) from aluminium by the action of cosmic rays are measured at the Mont Blanc (altitude 4600 m), the Aiguille du Midi (3840 m), and the Col du Lautaret (2070 m). They are2.3 ± 0.5,1.8 ± 0.3,and0.77 ± 0.18 atoms min^?1 kg^?1, respectively, in good agreement with the calculated production rates, 2.4, 1.7 and 0.6 atoms min^?1 kg^?1, respectively, at the three stations.Production rates of²⁴Na (T_1/2 = 15hours) from aluminium and magnesium are also measured at the Aiguille du Midi; the observed rates of3.4 ± 0.4and6.0 ± 1.7 atoms min^?1 kg^?1, respectively, agree well with the theoretically expected rates of 3.7 and 5.6 atoms min^?1 kg^?1.The production rates of³H,⁷Be,¹⁰Be,¹⁴C,²²Na,²⁶Al,³⁶Cl,³⁷Ar,³⁹Ar,⁵³Mn,⁵⁴Mn, and⁵⁵Fe in terrestrial rocks by the action of cosmic rays are calculated in order to show the possibility of applying the measurements of these cosmogenic radionuclides to the earth science.  相似文献   

Experimental study on the phase equilibria in the join CaMgSi2O6-CaCrCrSiO6 with special reference to the blue diopside     

Ko Ikeda  Kenzo Yagi 《Contributions to Mineralogy and Petrology》1977,61(1):91-106

The behaviour of tetrahedrally coordinated and octahedrally coordinated Cr³⁺ ions in diopside is discussed from the study on the join CaMg-Si₂O₆-CaCrCrSiO₆. The molecule CaCrCrSiO₆ decomposes into uvarovite+eskolaite and its maximum solubility in diopside is 6.7 wt percent at 940 ° C. Crystalline phases are diopside ss (ss is abbreviation of solid solution), uvarovite ss, wollastonite ss, spinel and eskolaite. The diopside ss is blue in colour. Its optical spectra were measured in the wavelenght range of 325–2600 nm, and assigned after tetrahedral configuration Td and octahedral configuration Oh. It is estimated that octahedral Cr³⁺ ions are in high spin state, while tetrahedral Cr³⁺ ions may be probably in low spin state. The _t and B are 10,300–10,370 cm^–1 and 429–432 cm^–1. The CFSE for tetrahedral low spin Cr³⁺ ions is nearly the same as that for octahedral high spin Cr³⁺ ions. The ionic radii of tetrahedral low spin Cr³⁺ ions calculated are 0.47–0.53 Å, shrinked from the radius of octahedral high spin Cr³⁺ ion (0.615 Å) as much as 14–24 percent. Petrologic implications of the result are also discussed.The first half of the D. Sc. dissertation of K. Ikeda presented to Hokkaido University in June, 1976  相似文献   

ACMEG‐TS: A constitutive model for unsaturated soils under non‐isothermal conditions     

Bertrand François  Lyesse Laloui 《国际地质力学数值与分析法杂志》2008,32(16):1955-1988

This paper introduces an unconventional constitutive model for soils, which deals with a unified thermo‐mechanical modelling for unsaturated soils. The relevant temperature and suction effects are studied in light of elasto‐plasticity. A generalized effective stress framework is adopted, which includes a number of intrinsic thermo‐hydro‐mechanical connections, to represent the stress state in the soil. Two coupled constitutive aspects are used to fully describe the non‐isothermal behaviour. The mechanical constitutive part is built on the concepts of bounding surface theory and multi‐mechanism plasticity, whereas water retention characteristics are described using elasto‐plasticity to reproduce the hysteretic response and the effect of temperature and dry density on retention properties. The theoretical formulation is supported by comparisons with experimental results on two compacted clays. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Nature and role of CO2 in some hot and cold HCO3/Na/CO2-rich Portuguese mineral waters: a review and reinterpretation     

José M. Marques  Paula M. M. Carreira  Luís Aires-Barros  Rui C. Graça 《Environmental Geology》2000,40(1-2):53-63

 At the northern part of the Portuguese mainland, the upflow zone of several hot and cold HCO₃/Na/CO₂-rich mineral waters is mainly associated with important NNE–SSW faults. Several geochemical studies have been carried out on thermal and non-thermal hydromineral manifestations that occur along or near these long tectonic alignments. The slight chemical differences that exist between these meteoric hot and cold HCO₃/Na/CO₂-rich mineral waters seem to be mainly caused by CO₂. δ¹³C_(TIDC) values observed in these groundwaters range between –6.00 and –1.00‰ versus V-PDB (V denotes Vienna, the site of the International Atomic Energy Agency; PDB originates from the CaCO₃ of the rostrum of a Cretaceous belemnite, Belemnitella americana, collected in the Peedee formation of South Carolina, USA) indicating a deep-seated (mantle) origin for most of the CO₂. Nevertheless, in the case of the heavier δ¹³C_(TIDC) values, the contribution of metamorphic CO₂ or the dissolution of carbonate rock levels at depth cannot be excluded. Concerning the hot waters, the lack of a positive ¹⁸O-shift should be attributed to water-rock interaction in a low temperature environment, rather than to the isotopic influence of CO₂ on the δ¹⁸O-value of the waters. Received: 9 August 1999 · Accepted: 8 March 2000  相似文献   

Origin of Early Carboniferous pseudo‐adakites in northern Brittany (France) through massive amphibole fractionation from hydrous basalt     

Mélanie Barboni  François Bussy  Massimo Chiaradia 《地学学报》2011,23(1):1-10

  相似文献