The article presents a method of forecasting the deformation of the land surface over large fields of underground gas storage facilities located in salt caverns. The solution allows for taking into account many parameters characterising the operation of underground gas storage facilities, such as cavern processes (leaching, enlargement, operational, etc.), their depth, distribution, diameter, shape, and many others. The advantage of the applied method over other available options is the possibility of using it for large fields of caverns while keeping the calculations simple. The effectiveness of the method has been proven for predicted surface subsidence for the EPE field with 114 underground caverns. The hypothesis was compared with the measurement outcomes.

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Determination of original state of stress in rock mass is a very difficult task for rock mechanics. Yet, original state of stress in rock mass has fundamental influence on secondary state of stress, which occurs in the vicinity of mining headings. This, in turn, is the cause of the occurrence of a number of mining hazards, i.e., seismic events, rock bursts, gas and rock outbursts, falls of roof. From experience, it is known that original state of stress depends a lot on tectonic disturbances, i.e., faults and folds. In the area of faults, a great number of seismic events occur, often of high energies. These seismic events, in many cases, are the cause of rock bursts and damage to the constructions located inside the rock mass and on the surface of the ground. To estimate the influence of fault existence on the disturbance of original state of stress in rock mass, numerical calculations were done by means of Finite Element Method. In the calculations, it was tried to determine the influence of different factors on state of stress, which occurs in the vicinity of a normal fault, i.e., the influence of normal fault inclination, deformability of rock mass, values of friction coefficient on the fault contact. Critical value of friction coefficient was also determined, when mutual dislocation of rock mass part separated by a fault is impossible. The obtained results enabled formulation of a number of conclusions, which are important in the context of seismic events and rock bursts in the area of faults.

The paper presents the results of analyses on tendency of bedded rock mass towards rockburst, carried out on the basis of laboratory tests of rock samples and determined indices, as well as by means of numerical calculations. The first part of the paper discusses selected parameters evaluating the tendency of rocks towards burst, on the basis of which the analysis was carried out in order to assess rockburst hazard in selected complexes of strata in Upper Silesian Coal Basin. Rockburst hazard in bedded rock mass is also analyzed with the use of numerical methods and the results of calculations of rock damage development in the exploitation front during coal deposit extraction are presented. Burst hazard of rock mass is studied through the changes of intensiveness of damage process in the area of exploitation front.Keywords: rockburst, rockburst hazard indices, numerical methods W artykule zaprezentowano wyniki analiz skłonności górotworu uwarstwionego do tąpań przeprowadzone na podstawie badań laboratoryjnych próbek skalnych i wyznaczonych na tej podstawie wskaźników oraz obliczeń numerycznych. W pierwszej części artykułu zaprezentowano wybrane wskaźniki służące do oceny skłonności skał do tąpań. Na podstawie wybranych wskaźników przeprowadzono analizę skłon-ności do tąpań wybranych kompleksów warstw skalnych GZW. Skłonność górotworu uwarstwionego do tąpań, analizowano również wykorzystując do tego celu obliczenia numeryczne. Zaprezentowano wyniki obliczeń rozwoju zniszczenia skał w przodku eksploatacyjnym podczas eksploatacji pokładu węgla. Skłonność górotworu do tąpań była analizowana poprzez zmiany intensywności procesu zniszczenia w otoczeniu przodka eksploatacyjnego.Słowa kluczowe: tąpania, wskaźniki skłonności do tąpań, obliczenia numeryczne