Uranium deposits, between which gas storage are being designed, the Rožná deposit and Olší deposit, are situated on the east edge of the Strážek Moldanubicum in Bohemian Masiff. Based on structural analysis it was possible to carry out the first rough prediction of potential weak zones in the rock mass. The structural analysis was also one of the supporting materials for determining the geometry and design method for the mine workings for the gas storage and for the advancing exploration of the gas storage region. Until now, the measurement of foliation planes and discontinuity planes in the survey crosscut V1-XXI and in a survey connecting gate GR1-XXI has been carried out. The results of interpretation of the measurement and monitoring of ductile elements (foliations) and joints (ruptures) as well as dislocations interpretation from the mine maps can be summarized and quoted in the contribution., Jiří Ptáček, Rostislav Melichar, Antonín Hájek, Petr Koníček, Kamil Souček, Lubomír Staš, Petr Kříž and Josef Lazárek., and Obsahuje bibliografii
The irregular distribution of stress in rock mass is a decisive factor for the origin of rock bursts. Besides, a sound knowledge of stress distribution is very important in the excavation of mine workings. Stress state is affected both by natural stress, including the gravitational, tectonic, hydraulic and residual stress and the stress induced by mining operations. Natural stress fields are defined by their geological structure and rock properties. It is important in mining practice to understand that there is a close relationship between recent and residual tectonic stress, as defined by tectonic evolution and tectonic structure. Since 1994, a large number of horizontal stress measurements have been carried out at a depth of 600 m to 800 m under the surface. The application of the results obtained from the measurements of stress and their comparison with the results of structural analysis and their generalization for the Karviná subbasin can be an important contribution to optimize the timespace designs of the mining activity., Petr Waclawik, Jiří Ptáček and Radomír Grygar., and Obsahuje bibliografii
Preferential flow paths in the crust, as caused by the presence of the Luchlompolo fault in the drilled section of the Kola Superdeep Borehole (SG-3) and the dip angle of the rock structural elements (layering, schistosity, banding), are favourable for migration of deep fluids to the Earth’s surface. An investigation of the structure, anisotropy and permeability of rocks under PT-conditions in the SG-3 section, in addition to the occurrence of He-isotopes, reveals that the high-permeability zones of the exposed crustal segment are related to two important structural elements of the section: in the upper zone - to the Luchlompolo fault, in the lower one to the contact between the Proterozoic and Archaean complexes. The obtained results on the rock samples from SG-3 indicate a rough correlation between permeability and elastic anisotropy of various rock samples. Simulating increased PT-conditions, corresponding to the relevant depths of 6-8 km document the overlapping temperature and pressure effect, i.e. resulting in a sharp decrease of rock permeability., Felix F. Gorbatsevich, Serafim V. Ikorsky and Andrey V. Zharikov., and Obsahuje bibliografii
To obtain the starting point for theoretical numerical computations the fibre reinforced concrete construction properties, adhesion of cement mixture with steel and polypropylene fibres and changes in its tension properties commensurate with number and weight percentage in the tested specimen were tested under laboratory conditions., Jiřina Trčková and Karel Řezba., and Obsahuje bibliografické odkazy
Evaluation of seismic loading in urban areas is not a simple process. The horizontal to vertical spectral ratio method technique has been often used for determination of site effect recently. Results from the re-interpretation of mining induced seismic events from Karviná region in frequency domain using archival databases will be presented in this study material. Also, spectra of continuous records (a bout two days) and evolution of spectra within a moving time window of the length 10 seconds are presented. These continuous records were registered on two places with different geological conditions., Zdeněk Kaláb and Alexey A. Lyubushin., and Obsahuje bibliografické odkazy
Generally, rock material failure is controlled by cracks under specific conditions. The study of rock fracture toughness belongs to the current frequent directions of research in the area of rock failure. The present paper describes the effects of parameters influencing the resultant properties of rock materials (bending rate, rock moisture) during fracture toughness measurement of different kinds of rocks (sandstone, marble, granite). The highest fracture toughness values were found in the marble samples. This is probably due to the inner structure of analysed marble, which is composed of only one mineral (calcite) and also has a lower porosity than the used granite. The lowest fracture toughness values were found in the sandstone sample, and reached c. 17-30 % of the measured fracture toughness values of the analysed granite and marble samples. As in the case of the other mechanical properties of rocks (e.g. uniaxial compressive strength) also in the case of higher sandstone (carboniferous) moisture the fracture toughness values decrease and its deformation ability increases. Preparation of samples for fracture toughness tests and performance of these tests are more complicated than in the case of tensile tests (e.g. the Brazilian test) and therefore this contribution presents a comparison between fracture toughness of analysed rocks and tensile strength values. The measured data in this study considering the fracture toughness tests and Brazilian tests were compared with results published by Zhang (2002)., Leona Vavro and Kamil Souček., and Obsahuje bibliografii
Using the FLAC3D numerical simulation method, the characteristics of mining stress evolution, fault activation patterns, and fault energy evolution characteristics are simulated and analyzed in the process of the footwall and hanging wall working face heading to a normal fault. The study shows that the fault cut off the mining stress propagation of overlying strata, and the stress blocking effect due to the fault is evident. When working faces head towards a fault, the abutment pressure and the vertical stress of the surrounding rock increase first and subsequently decrease. The abutment pressure of the coal wall and fault is highest when the distances to the fault are 40 m and 30 m for the footwall and hanging wall working faces, respectively. Moreover, the hanging wall mining stress is higher than the footwall mining stress. Fault activation in high-located strata precedes that in low-located strata when working faces head towards the normal fault. Energy is gradually accumulated before unstable fault events take place because of mining, and fault instability quickly releases a lot of energy. The mining stress concentration and fault activation due to faults easily result in rock bursts and mine seismicity, Wu Quan-sen, Jiang Li-shuai and Wu Quan-lin., and Obsahuje bibliografické odkazy
The Hronov-Poříčí Trough represents the easternmost part of the Trutnov-Náchod Depression. The NW-SE striking structure was formed due to the post-Cretaceous flexural folding and is filled with the Upper Cretaceous sediments. Both the NE and SW margins of the trough are bounded by flexures with the Upper Cretaceous strata dipping 40-60° towards the axis of the trough. The NE flexure is situated close to the parallel Hronov-Poříčí Fault Zone. Up to now, it is not fully known, in what extent the normal faulting was involved in the evolution of the structure. From the geomorphological point of view, the normal fault constraints of the trough seem to be acceptable, as the surface topography of its present margins exhibit many signs typical for fault scarps. However, the existence of a fault system bounding all round the Hronov-Poříčí Trough has not b een proved by any geological research. Hence the geophysical research was carried out on both sides of the NW part of the trough to support one of these hypothesis. Five geoelectrical profiles were measured in the area and the fault system was proved on the NE side of the trough. On the SW boundary the fault system was not found. Thus it seems, that the NE boundary is controlled by fault tectonics, whereas the SW boundary is rather formed by a simple flexure., Jan Valenta, Vladimír Stejskal and Petra Štěpančíková., and Obsahuje bibliografické odkazy
In the frame of advanced studies of coal structure the temperature conditions of coal origin were investigated through thermal stability of aluminum complexes in coal substance. These compounds were discovered by solid-state nuclear magnetic resonance measurements of 27Al as a part of coal substance closely bonded to organic mass of coal. In obtained spectra, Al-hexaphenoxide and Al-tetrahydroxy-diphenoxide complexes were identified. These complexes were further prepared and their thermal stability tested by thermal analysis method. It was found that a) they can originate under room temperature and atmospheric pressure and b) they are thermally stable only up to approximately 85 or 95 °C. As both Al-hexaphenoxide and Al-tetrahydroxy-diphenoxide complexes are the integrated constituents of coal substance it can be deduced that, in the beginning, coal was formed under very mild thermal conditions. As investigated materials, coals and clays from the Czech basins and gagatite from Poland were measured., Pavel Straka and Jana Náhunková., and Obsahuje bibliografii
This paper focuses on the impact of changes in temperature on one bay of St Vitus’ Cathedral in Prague Castle. The objective of the study is to simulate as correctly as possible the distribution of temperatures in the structure, and then to compute the thermal dilatation movements. Theoretical simulation of dilatation movements involves simulating the temperatures in the structure and then computing the displacements. Insolation and changes in air temperature around the structure are included in the temperature simulation. The computed temperature fields are used as a loading for computing the forces and deformations of one bay of St Vitus’ Cathedral. The theoretical deformation values obtained by means of the 3-D finite element model were compared with the measurements. The computed surface temperatures were also confronted with the surface temperatures measured in the interior and on the exterior of the cathedral. The results obtained from the simulations correspond well with the measured surface temperatures and deformations., Pavel Beran, Jiří Máca and Petr Fajman., and Obsahuje bibliografii