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Wyszukujesz frazę "Kopecky, M." wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Rock pore structure as main reason of rock deterioration
Autorzy:
Ondrášik, M.
Kopecký, M.
Powiązania:
https://bibliotekanauki.pl/articles/178163.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mechanical weathering
rock deterioration
adsorbed water
adsorbed water freezing
rock porosity
freeze-thaw loss
proces zamrażania i rozmrażania
wietrzenie mechaniczne
adsorpcja wody
porowatość skał
Opis:
Crashed or dimensional rocks have been used as natural construction material, decoration stone or as material for artistic sculptures. Especially old historical towns not only in Slovakia have had experiences with use of stones for construction purposes for centuries. The whole buildings were made from dimensional stone, like sandstone, limestone or rhyolite. Pavements were made especially from basalt, andesite, rhyolite or granite. Also the most common modern construction material – concrete includes large amounts of crashed rock, especially limestone, dolostone and andesite. However, rock as any other material if exposed to exogenous processes starts to deteriorate. Especially mechanical weathering can be very intensive if rock with unsuitable rock properties is used. For long it had been believed that repeated freezing and thawing in relation to high absorption is the main reason of the rock deterioration. In Slovakia for many years the high water absorption was set as exclusion criterion for use of rocks and stones in building industry. Only after 1989 the absorption was accepted as merely informational rock property and not exclusion. The reason of the change was not the understanding of the relationship between the porosity and rock deterioration, but more or less good experiences with some high porous rocks used in constructions exposed to severe weather conditions and proving a lack of relationship between rock freeze-thaw resistivity and water absorption. Results of the recent worldwide research suggest that understanding a resistivity of rocks against deterioration is hidden not in the absorption but in the structure of rock pores in relation to thermodynamic properties of pore water and tensile strength of rocks and rock minerals. Also this article presents some results of research on rock deterioration and pore structure performed on 88 rock samples. The results divide the rocks tested into two groups – group N in which the pore water does not freeze even when the temperature decreases to –20 ºC, and the second group F in which the pore water freezes. It has been found that the rocks from group N contain critical portion of adsorbed water in pores which prevents freezing of the pore water. The presence of adsorbed water enables thermodynamic processes related to osmosis which are dominantly responsible for deterioration of rocks from group N. A high correlation (R = 0.81) between content of adsorbed water and freeze-thaw loss was proved and can be used as durability estimator of rocks from group N. The rock deterioration of group F is caused not only by osmosis, but also by some other processes and influences, such as hydraulic pressure, permeability, grain size, rock and mineral tensile strength, degree of saturation, etc., and the deterioration cannot be predicted yet without the freeze-thaw test. Since the contents of absorbed water and ratio between adsorbed and bulk water (of which the absorbed water consists) is controlled by the porosity and pore structure, it can be concluded that the deterioration of some rocks is strongly related to rock pore structure.
Źródło:
Studia Geotechnica et Mechanica; 2014, 36, 1; 79-88
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Horizontal drains as effective measure for landslide remediation
Autorzy:
Kopecký, M.
Ondrášik, M.
Antolová, D.
Powiązania:
https://bibliotekanauki.pl/articles/178941.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rekultywacja osuwiska
odwierty odwadniające
drenowanie
dreny poziome
landslide remediation
drainage borehole
drainage
horizontal drains
Opis:
Decrease of groundwater table level or decrease of buoyancy effects of groundwater is one of the most important landslide remediation measures. In Slovakia as well as in the world the horizontal drainage boreholes are often used for the landslide remediation. The article describes 40 years’ experience with use of the horizontal drainage boreholes in Slovakia, particularly in terms of their effectiveness and long-term functionality.
Źródło:
Studia Geotechnica et Mechanica; 2013, 35, 1; 129-142
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Complex geodetic and photogrammetric monitoring of the Kraľovany rock slide
Autorzy:
Fraštia, M.
Marčiš, M.
Kopecký, M.
Liščák, P.
Žilka, A.
Powiązania:
https://bibliotekanauki.pl/articles/92003.pdf
Data publikacji:
2014
Wydawca:
Główny Instytut Górnictwa
Tematy:
rock slide
laser scanning
image scanning
RPAS photogrammetry
osuwisko masywów skalnych
skanowanie laserowe
skanowanie obrazu
fotogrametria RPAS
Opis:
Purpose The complex monitoring of rock slides with the size of 16 ha in order to predict the development of other slides and prevent possible human and material losses. Methods Precise geodetic point measurement, terrestrial laser and image scanning and aerial photogrammetry were used to obtain detailed knowledge about the geometry and behaviour of the rock slide. Except for terrestrial images, the images were taken using an SLR camera (set on a motor paraglide) and a compact camera (set on a remotely piloted system). The state and condition of the locality before the rock slide was taken from archive images taken by a digital large format camera. Results Vectors and velocities of the displacements of discrete points were determined with high precision; the changes in quarry wall surfaces were determined by laser and photogrammetry scanning. Finally, high resolution orthophotomosaics of the site were generated using aerial photogrammetry at each observation point. Practical implications The termination of mining and the design of the remediation works were determined according to the results of the measurements. Also, monitoring was carried out in order to observe any changes due to the implementation of a highway project based in the localisation. Originality/ value Complex geodetic and photogrammetric monitoring of rock slides offers detailed information about slide surfaces and has previously been used in Slovakia on a significant scale.
Źródło:
Journal of Sustainable Mining; 2014, 13, 4; 12-16
2300-1364
2300-3960
Pojawia się w:
Journal of Sustainable Mining
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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