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2. A model of rock mass fracturing ahead of the longwall face as a consequence of intensity of exploitation
- Creator:
- Drzewiecki, Jan and Makówka, Janusz
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, 7, and 551
- Language:
- English
- Description:
- In Czech and Polish underground hard coal mines of the Upper Silesian Coal Basin high-energy seismic phenomena are periodically recorded, the sources of which are located ahead of the longwall. Generally, these types of tremors are rooted in very strong, thick layers of sandstone, which are subject to the deformation border. The consequences are discontinuities and cracks with a range depending on the mechanical properties of destroyed rocks: the mechanical parameters of layers. Forecasting methods, developed in the Central Mining Institute, for stress concentration, seismic energy, fault zone and range, together with methods of rock fracturing using liquid or explosives, ,allow precise identification of suitable locations for controlled fracturing of rock mass with a pre-established direction. The size and range of discontinuities have an impact on mining parameters, dependent on basic exploitation intensity and expressed by the average daily progress of the longwall face. The rockmass is locally weakened because of exploitation or technical measures of discontinuities in the roof-rock on the longwall face. To prevent rockburst, measures are needed to reduce the amount of energy accumulating in the rockmass in the area of the longwall face. Knowledge of where stress is concentrated is extremely important for the development and implementation of effective preventative methods. For many years several research centres have been working on defining the range of these areas. In this paper, basic information is presented on methods developed by Central Mining Institute and used in Polish hard coal mines for forecasting energy concentration and assessing how it can be reduced., Jan Drzewiecki and Janusz Makówka., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. A new approach for the determination of onset of failure points during laboratory strength testing of rocks
- Creator:
- Mamurekli, Deniz
- Format:
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- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodynamika, skály, geodynamics, rocks, pre-failure points, uniaxial tests, load-deformation, 7, and 551
- Language:
- English
- Description:
- Estimating the pre- failure points for rocks during laboratory testing is not a trivial task. In this study, a new approach is introduced that utilizes change in the slope of the load-deformation curves of rock in the loading cycle for marking the onset of failure point during uniaxial test of a given rock. At each step, load-deformation data footprints of the rock under test are inspected and a decision is made whether the failure has started or not. The load-deformation data obtained from different tests of different rocks are examined including; Norite, Granite, Limestone, Sandstone, Siltstone and Marble. The computational results over 154 cored rock samples show that the proposed approach locates the onset of failure point for a given rock with an acceptable degree of accuracy., Deniz Mamurekli., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. Accuracy of the relative gravity measurement
- Creator:
- Lederer, Martin
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, accuracy, precision, relative gravimetry, 7, and 551
- Language:
- English
- Description:
- Precise relative gravimeters achieve the internal precision about a few μGal 1, even in field conditions. Nevertheless this precision is in fact concerned with the instant of measurement and can not be confused with the accuracy of the gravity at the gravity station, which is influenced by other effects. The best approach of these two values is question of high-quality elimination of instrumental errors and time-variable disturbing effects affecting the relative gravity measurements., Martin Lederer., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5. Active tectonics in the Eastern Margin of the Bohemian massif: based on the geophysical, geomorphological and GPS data
- Creator:
- Lubomil Pospíšil, Pavel Roštínský, Otakar Švábenský, Josef Weigel, and Witiska, Michal
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodynamika, GPS (navigační systém), geodynamics, GPS (navigation system), active tectonic, morphology, movement tendencies, Waitzendorf and Diendorf faults, 7, and 551
- Language:
- English
- Description:
- One of the leaved out fault active systems at Southern Moravian can be considered the so called Diendorf - Čebín tectonic zone (DCTZ), that is seismically active in its southern segment (in Austrian). The Waitzendorf fault is a part of the DCTZ, with intensive morphological signs. The terrain recognizance along the eastern margin of the Dyje Dome confirmed many indi cations showing evidence of geodynamic activity. The facets, old land slides and rock falls indicate recent activity in the environs of Znojmo area. The paper offers interpretation of the geodetic results (GPS) using morphological and geophysical data from all area of the DCTZ ., Lubomil Pospíšil, Pavel Roštínský, Otakar Švábenský, Josef Weigel and Michal Witiska., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6. Amplitude spectra of surface waves generated by shot-hole explosions
- Creator:
- Holub, Karel
- Format:
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- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, Rayleigh waves, shot-hole explosions, spectral analysis, amplitude spectra, 7, and 551
- Language:
- English
- Description:
- The object of the research was to investigate the spectral properties of Rayleigh-type surface waves, generated by shot-hole explosions during seismic refraction experiments which were carried out in the area of the Bohemian Massif and West Carpathians. The records of displacement amplitudes were spectrally analyzed and prevailing frequency fp, relative Δfr and absolute widths of the spectra Δfa were chosen as essential parameters. Whilst the prevailing frequencies were recorded within the interval f ÷ 0.80 - 3.70 Hz at the site of the observations, situated on the territory of the Bohemian Massif, the respecti ve frequency range f ÷ 0.80 - 2.6 Hz was found in the West Carpathians. Some functional dependences of the spectral amplitude parameters on epicentral distance were observed and regularities of their decrease were defined. Moreover, the influence of local seismogeological conditions at the shot point as well as at the site of observation occurred., Karel Holub., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7. Application of resistivity imaging to recognition of geological structure in the area of shallow Zn-Pb ore bodies: (preliminary study)
- Creator:
- Jochymczyk, Krzysztof, Cabala, Jerzy, and Poreba, Artur
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, resistivity imaging, geophysics ore recognition, Zawiercie Zn-Pb ore deposits, 7, and 551
- Language:
- English
- Description:
- Depletion of exploited mineral ore resources and their constant price increase have contributed to active interest in recognition and exploitation of new workable deposits. Exploration work which has been carried out in the vicinity of non-exploited ore areas such as Klucze, Zawiercie and Laski results in confirmation of Zn-Pb commercial deposits. In this region Zn-Pb ores occur in the Devonian and Triassic carbonate formation at a depth of 70 - 80 metres under the surface. Geological recognition is based on the analysis of data taken from bore-holes. To determine the mode of the ores occurrence and service conditions, it is necessity to work out a spatial image of overburden structure. For this reason resistivity measurements with highly distributed LUND Imaging System were introduced in the area of Zawiercie I. The studies were carried out according to three measuring protocols: Schlumberger, Wenner and dipole-dipole. The measurements were performed along three parallel six-hundred-metre profiles. The resistivity cross sections were elaborated using Res2D software. The results of the geophysical research were correlated with the data taken from bore-holes in order to testing the efficiency of applied geoelectrical methods. The study showed a significant diversification of geoelectric characteristics of the rockmass and thus it allowed to recognise accurately the overburden structure of the deposit and to locate precisely zones of faulting. In future, the applied geoelectrical methods are certainly to be used for localization ore bodies at a considarable depth range., Krzysztof Jochymczyk, Jerzy Cabala and Artur Poreba., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8. Application of short-time GNSS solutions to geodynamical studies
- Creator:
- Araszkiewicz, Andrzej, Bogusz, Janusz, Figurski, Mariusz, and Szafranek, Karolina
- Format:
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- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, ASG-EUPOS, short-time solutions, frequency analysis, periodic signals, 7, and 551
- Language:
- English
- Description:
- The paper presents the results of research related to the application of GNSS solutions in short observational periods in geodynamical investigations. Authors used the 3-hour solution appointed from hour-long interval of about 30 chosen stations on mountainous terrains from over 100 which were worked out. The main aim was to check the correctness of such solutions by the comparison with the daily ones. Some outliers in East component could testify, that tropospheric or ionospheric models used in the data adjustment are not sufficient for so short-time solutions. The second principal problem, which was considered in the present work is the ability to detect diurnal and sub-diurnal oscillations in changes of permanent stations’ coordinates. Results show unambiguously, that such oscillations appear in all analysed stations. In the paper there are examples of stations with dominant oscillations in different frequencies. The clear homogeneous in the frequencies was not found among any group of stations. It is therefore difficult to affirm, if their origin comes purely from the geodynamical phenomena., Andrzej Araszkiewicz, Janusz Bogusz, Mariusz Figurski and Karolina Szafranek., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
9. Assessment of factors and conditions influencing bank stability of future lakes
- Creator:
- Spanilá, Tamara, Kudrna, Zdeněk, Vladislav John, Hartvich, Filip, and Chour, Vladimír
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, jezera, geodynamika, lakes, geodynamics, flooding of residual mining pits, dangerous geodynamic phenomena, stability of banks and slopes, 7, and 551
- Language:
- English
- Description:
- While including gradual long-term flooding of individual residual mining pits, the re-vitalization program of the Podkrušnohorská brown-coal basin area has to assure - beside general water quality standards - satisfactory stability level of future lake banks and their wider environment as required for safe usage of future water lakes. General assessment of factors and conditions influencing bank and/or slope stability of future lakes was realized within the frames of the Czech Republic Academy of Sciences grant project. The grant project solutions include a study of exogenous processes on localities where the mining has been terminated. Also, prognoses were developed on behaviour of future banks during flooding and subsequent operation of future lakes. The presented paper is focused on assessment of mayor factors that participate on initiation and intensity of the bank abrasion and sliding deformations., Tamara Spanilá, Zdeněk Kudrna, Vladislav John, Filip Hartvich and Vladimír Chour., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
10. Assessment of P-wave anisotropy by means of velocity elipsoid
- Creator:
- Petružálek, Matěj, Vilhelm, Jan, Lokajíček, Tomáš, and Rudajev, Vladimír
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, foliation, loading, ultrasound sounding, elastic wave velocity, anisotropy, 7, and 551
- Language:
- English
- Description:
- A method for estimation of elastic wave velocity anisotropy based on ultrasonic sounding data during rock-sample loading was developed. The subject matter of the method is approximation of ultrasonic sounding data by triaxial velocity ellipsoid. The applicability of proposed method was verified on investigation of anisot ropic rock samples. Laboratory loading of migmatite samples was realized under various mutual orientations between acting force direction and rock foliation - perpendicular, parallel and under 45°. P-ve velocity of ultrasound waves was monitored by 8 sensors network. The velocity ellipsoid was computed and changes of sizes and waorientation its main axes during loading were analyzed for separate experiments with regard to loading level. It was found, that independently to mutual orientation between rock foliation and loading direction, the minimum velocity vector turns to perpendicular direction to final rupture plane and maximum velocity vector turns to the plane of final rupture., Matěj Petružálek, Jan Vilhelm, Tomáš Lokajíček and Vladimír Rudajev., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public