Brown coal open pit mining in the basin under Krušné Hory Mts. came to contact with slopes of the mountains, and a problem of the stability in high and steep slopes in the crystalline rock became an important question. The question concerns Jezeří Castle built on the top of one of the hills in a most endangered section where even a supporting pillar in the sediments under the slope toe was left to support the slope. As a result, an extensive monitoring program regarding deformations was initiated in the region. The program involved several methods and some important results are discussed. The results that are displayed concern mainly measurements done in geophysical tiltmeter stations in two underground galleries driven into the two steep slope sections showing most dangerous situation, as well as extensometers located in the same locations. Long-term monitoring revealed a tectonic deformation process of a natural origin that is registered as slow and systematic tilts. Besides, it revealed several periods of anomalies that are of basic importance. During a long period of observation from 1982 till 2005 three important deformation anomalies were registered: the event of 1994, the event of 2002, and the event of 2003/2004. The first and the third event have been classified as of a large regional character that affected a wide mountainous area and could be interpreted as a tectonic impulse originating within the mountainous structure of the so called "Dome of Hora Svaté Kateřiny". The second event has been considered different, strictly connected with extreme precipitation of August 2002. The anomaly was evidenced even deep in the crystalline, so that it could not be seen as of a superficial character only. The movement which was registered at that time was oriented right into the pillar supporting the slope., It is concluded that it was a short manifestation of instability in the critical profile "Jezeří - pillar", which stresses the important stabilisation function of the supporting pillar without which the profile will be probably destabilised., Blahoslav Košťák, Bohumil Chán and Jan Rybář., and Obsahuje bibliografii
The research is focused on the feasibility analysis of a numerical model describing the field of strains generated by mining-induced subsidence caused by a deep underground coal extraction, which may contribute to the formation of Earth fissures. The finite elements method and Knothe’s theory were used in the research. The geomechanical modeling was applied for defining zones of strains and maximum horizontal deformations of the terrain. Knothe’s theory was employed for defining boundary conditions of the geomechanical model. The parameters of the empirical and geomechanical models were scaled out on the basis of geodetic surveys in the mining area. The results of geomechanical modeling were compared with the geodetic surveys to select the best model. The presented research confirmed high congruence between the results of modeling with the finite elements method and observations of vertical movements on the surface. The results of modeling also confirmed the assumed highest stress in areas where earth fissures were observed. The proposed solution may be a new research tool applicable to areas where earth fissures potentially occur. and Malinowska Agnieszka A., Misa Rafał, Tajduś Krzysztof.