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Numerical applications of geometric-integral theory of underground mining effect of Professor Stanisław Knothe

Białek J.

Prace Instytutu Mechaniki Górotworu PAN

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2018

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T. 20, nr 1

69--80

EN

The paper presents a general space-time variant of the geometric-integral theory of influences of Professor Stanisław Knothe. The theory describes the deformations of rock mass and surface area caused by underground mining. Then, calculation algorithms which allow to apply the theory in computer programs were presented. The first of the algorithms worked out in the 1970s by B. Drzęźla [10] assumes that the calculations are carried out in the polar coordinate system. It is characterized by extraordinary numerical effectiveness and it allows to approximate the mining process with any polygon. But the prediction results describe only the final deformation states, which is a kind of limitation. The second described algorithm, worked out by J. Białek [2, 3], uses the relations in a rectangular coordinate system. It allows to include in calculations the space-time evolution of the multi-panel and multi-bed underground mining exploitation. The programs also allow for the description of influence delay with respect to the completed mining exploitation, in line with the differential equation proposed by S. Knothe. The results of the prediction can involve the increment of deformations in any preset time interval, or extreme deformations in that time interval. Finally, the main reasons are presented, explaining why the application of S. Knothe theory has been popular in Poland and worldwide for 65 years.

2

Wykorzystanie badań modelowych na ośrodku sypkim pionowo niejednorodnym do analizy kształtowania się przemieszczeń w brzeżnej części niecki osiadania

Cygan J., Leśniak J., Walaszczyk J.

Prace Instytutu Mechaniki Górotworu PAN

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2004

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Vol. 6, no. 1-2

47--58

PL

Wykonano eksperymenty na ośrodku sypkim pionowo jednorodnym i pionowo niejednorodnym, przy czym średnia gęstość w całym obszarze modelu we wszystkich eksperymentach była podobna. Uzyskane wyniki pozwalają na stwierdzenie wpływu poszczególnych warstw w eksperymentach na ośrodku niejednorodnym na przebieg przemieszczeń i odkształceń w funkcji współrzędnej pionowej. Przy powierzchni modelu wartości przemieszczeń są zbliżone dla modeli: z ośrodkiem jednorodnym i z ośrodkiem niejednorodnym, w którym dolną warstwę stanowił ośrodek zagęszczony – ma to związek z podobną średnią gęstością w całym modelu w obydwu tych eksperymentach. Uzyskane wyniki mogą być wykorzystane przy prognozowaniu wpływów eksploatacji.

EN

The authors performed the empirical investigations of the behaviour of homogeneous and vertically nonhomogeneous loose medium. For each experiment the material was of the same mean density with respect to entire model area. The measurements confirmed the influence of each layer of the non-homogeneous model on the values of its displacements and deformations to be the functions of the vertical co-ordinate. It has been recorded that at the upper layer of the model the values of displacements for the homogeneous model are the same as the values of displacements for the non-homogeneous model in which the density of lower layer was greater on comparison to the remaining layers. Such a situation is probably related to the uniform mean density with respect to the entire model area. The results of the paper may be applied for the prediction of the influence of mining exploitation on the behaviour of Earth surface.

3

Outburts of gas and rocks in viev of laboratory experiments

Wierzbicki M.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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1999

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Vol. 47, nr 1

63-72

EN

The results presented in this paper are a successive contribution to investigations on the couse of gas and coal outbursts phenomena, initiated under laboratory conditions. The paper presents results of experiments carried out in order to assess the impact to pressure wave reflected from the open end of the pipe on the course of the outburst. Results of subsequent experiments were divergent. Installation of additional manometers revealed assymmetry of the outburst front despite axial symmetry of the experimental stand and coal briquette. The cause of this asymmetry was briquitte. An improved design of the head was described.