National Repository of Grey Literature 7 records found  Search took 0.00 seconds. 
Rock strength anisotropy - interpretation of laboratory tests
Vilimová, Anna ; Rott, Josef (advisor) ; Kučera, Petr (referee)
Anizotropní materiál má v různých směrech různé vlastnosti. Anizotropie pevnosti je zvláštní typ chování pevnosti v závislosti na podobě struktury horniny. Vliv na její velikost má zejména úhel mezi směrem zatížení a plochou oslabení, důležité jsou ale i další parametry jako je tvar a velikost vzorku, vlhkost aj. Podle tvaru této závislosti můžeme anizotropii rozdělit na "U type", "shoulder type" a "undulatory type" nebo ji můžeme členit podle způsobu jejího vzniku na přirozenou a vyvolanou. Pro výpočet pevnosti anizotropních materiálů existuje celá řada vztahů, většina z nich empiricky odvozená z velkého množství laboratorních zkoušek. V současné době nejpoužívanějším a nejkomplexnějším je Hoek-Brownovo kritérium porušení. Nejčastějším způsobem interpretace anizotropie pevnosti je grafické zpracování obálek pevnosti a závislosti napětí při porušení na úhlu mezi směrem zatížení a plochami oslabení. Kombinací těchto dvou grafů je možné vytvořit plochu porušení horniny. Skutečnost, že hornina nemá ve všech směrech stejnou pevnost, a způsob, jak anizotropii charakterizovat a spočítat její velikost, je zásadní zejména pro návrhy geotechnických konstrukcí a určení napěťového stavu horninového masívu.
Hoek - Brown failure criterion and importance of triaxial testing in a project of deep geological repository.
Onysko, Radek ; Rott, Josef (advisor) ; Pruška, Jan (referee)
Goal of this paper is defining Hoek - Brown failure criterion for samples of granodiorite from possible site of Czech deep geological repository - Brezovy potok. Paper includes triaxial testing, defining HB failure criterion for intact rock, rock massif and evaluation of available data. Other methods for defining parameters of HB failure criterion (eg. GSI and mi) are also explored. Comparisons for all parameters and data are given. Paper is concluded with simple numerical model, using results from laboratory testing and literature review.
Some railway tunnels of old era in territory of Czech Republic
Černý, Tomáš ; Rott, Josef (advisor) ; Malát, Richard (referee)
The Bachelor thesis deals with some tunnels from the total number of 120 railway tunnels build in the period 1848-1910 in the territory of the Czech Republic. The aim of these admirable buildings was the research for masonry, geology and rock strength. The introductory articles are devoted to the classical tunneling methods used in earlier times. As a result of today's higher operating speeds of trains, which was not taken into account when initially planning the lining and limitation to the use of stone and wood only. The work includes the most frequent reconstruction methods for tunnel optimization, the possibility of faster transport and their stability. It has been shown that, for the purpose of possible reconstruction, it is necessary to count on the considerable strength of the masonry which, even after 100-170 years, often does not show signs of deep degradation.
Some railway tunnels of old era in territory of Czech Republic
Černý, Tomáš ; Rott, Josef (advisor) ; Malát, Richard (referee)
The Bachelor thesis deals with some tunnels from the total number of 120 railway tunnels build in the period 1848-1910 in the territory of the Czech Republic. The aim of these admirable buildings was the research for masonry, geology and rock strength. The introductory articles are devoted to the classical tunneling methods used in earlier times. As a result of today's higher operating speeds of trains, which was not taken into account when initially planning the lining and limitation to the use of stone and wood only. The work includes the most frequent reconstruction methods for tunnel optimization, the possibility of faster transport and their stability. It has been shown that, for the purpose of possible reconstruction, it is necessary to count on the considerable strength of the masonry which, even after 100-170 years, often does not show signs of deep degradation.
Railroad tunnel Praha-Beroun - as an example of underground structure in challenging karstic aresa
Belokopytov, Daniil ; Rott, Josef (advisor) ; Malát, Richard (referee)
This paper discusses impressive project of the tunnel between Prague and Beroun. The length of the structure, spreading up to 25 km, leads to need of overcoming many risks, which may the tunnel encounter. The text is focused on specific issues typical for areas built by karstic rocks, which generally present one of the most dangerous environment for building architectural projects of any kind. It concentrates on description of Bohemian karst and karstic features, which are likely to appear in studied area. It strives for delimintion of risks and suggestion of proper investigtion and remedition methods, suituable for given project. A part of the paper is a brief introduction into main tunneling technology, applicable for tunneling construction and discussion of possibilities of particular tunneling method.
Collapse of a deep excavation Nicoll Highway in Singapore
Polívková, Klára ; Mašín, David (advisor) ; Rott, Josef (referee)
The bachelor thesis is a recherche about a collapse of deep excavation and adjacent Nicoll Highway. The incident occurred on 20th April 2004. The project was called The Circle Line and it was construction of underground railway line. A main reason why the retaining system failed was incorrect setting of Mohr-Coulomb material model in Plaxis program.

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