| With the strength and depth of coal mining in our country rising, the number and strength of rock burst in coal mine present a trend of increasing; therefore, rock burst occurring in roadway caused by mine earthquake became more serious. Mining under protective layer has good weaken effect on rock burst; however, weaken effect of protective layer is not carried out detailed research. According to this situation, this paper analyzes the destruction mechanism of surrounding rock of roadway. Using experimental research, dynamic calculation, simulation and engineering case analysis and other research methods, put forward a method to determine the reasonable layout of the roadway and the rock burst danger with minimal risk and damage threshold reference value. The main conclusions are as follows:(1) Based on the relation between the rate of energy input and failure mechanism and failure modes of rock, analysis internal micro-cracks activities and failure modes of rock under different energy input rate, the results show that: the greater the rate of energy input is, the more severe failure modes of rock is, that the higher the mine earthquake energy level is, the more severe the rock burst occurring in roadway is.(2) According to the dynamics circulations, this paper explores distribution law of the dynamic stress field around the surrounding rock in roadway caused by seismic wave, the results showed that: with the wavelength becoming shorter gradually, radial stress field distribution characteristics become from the O to pour type D, and hoop stress field distribution characteristics become from the O to θ. In other words, when wavelength is longer, the dynamic stress field stress caused by seismic wave is uniform around the roadway. Therefore the destruction of roadway is integral and instantaneous. When the wavelength is shorter, the distribution of the dynamic stress field around the roadway caused by seismic wave is different, and the destruction of roadway has spatial characteristics.(3) Using FLAC2 D numerical simulation software, explore the different response of roadway in different lithology to the mine earthquake and with the laws of mine earthquake, geological conditions and demand of roadway, put up the reasonable arrangement of roadway. The results showed that: The larger the energy level of mine earthquake is, the more serious damage to the impact of the roadway. For example, in this simulation, mine earthquake level by the 105 J to 106 J, the roadway bearing capacity gradually instability. The stronger the self-stability of the rock is, the harder the rock burst occurs, however, the easier the surrounding rock in roadway store energy; therefore, considering the roadway needs, geological conditions and the laws of the mine earthquake to determine the reasonable arrangement of the roadway.(4) Using FLAC2 D numerical simulation software, explore the action rule of mine earthquake to the roadway under the structure of protective layer. The results showed that: protective layer structure has a good protective effect on rock burst prevention, Such as 3m thickness of protection layer can reduce the three-level mine earthquake. However, the larger the energy level of the mine earthquake, the more severe the response of the roadway under the protective layer structure. Therefore, for security reasons, the roadway should be disposed under the protective layer structure. However, the monitoring of rock burst should be strengthen and if necessary, puts the concrete preventing measures.(5) In practice, make a strong mine earthquake induced rock burst cases and damage laws of roadway caused by cumulative mine earthquake in zhaolou coal mine as research objective. The characteristics of strong mine earthquake induced rock burst are explored and the actual impact failure value and the reasonable arrangement of roadway are determent.This thesis has 50 Figures, 10 tables, 105 references. |
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