| Rock burst is a kind of dynamic phenomenon of coal and rock mass which is very destructive. With the continuous increase of China’s coal mining depth, the probability of rock burst is also rising. China’s first rockburst in 200 m depthunderground coal mine. The new <Coal Mine Rules> will be published regulations: all excavation depth more than 400 m of the coal mines, must go through the detection of rockburst. So now more and more people in academic circles pay a attention to coal mine rockburst and a mechanism of rock burst is widely accepted. That is the elastic energy in coal and rock overload, makes coal and rock cannot maintain the limit equilibrium state, and the time of releasing elastic energy is very short, which resulted in detect the rock burst more difficulty.The prediction of rock burst is inaccuracy for its random happen and suddenly. The occurrence of randomness and the views of mechanism on rock burst aredifferent,both of them caused the uncertainty of the prediction of rock burst. The coal and rock thrown by the rock burst causes damage to the personnel in the working face,tunnel space and the mechanical equipment. Thus, rockburst, as a affected by the geological conditions of and is related to the process of mining disastersclosely, the destructive power of coal face and roadway has great threat and coal and rock in the release of energy moment will produce sound waves caused by vibration, affecting the scope will be broader, it is easy to cause working surface support dumping and damage, thrown out of the coal and rock mass can easily lead to blockage of roadway and working face. When the degree of rock burst is more severe, it will be accompanied by a strong earthquake, it may also spread to the ground caused by ground subsidence, damage to buildings above the ground. In recent years, domestic and foreign experts for rockburst have done a lot of research, but because of the rockburst is random and sudden, before its occurrence did not obvious signs and indicators to predict rock burst may occur. There are a lot of factors of rockburst, between the various factors mutual effect of rock burst intensity did not an accurate indicator to judge, so of rockburst prediction and prevention is not to completely eliminate the degree, in coal mine disaster is difficult to overcome the difficulties.The Yao Shan Mine as the research target, because Yao Jia Shan mine after years of mining the mining depth deepening, has reached the average depth of 1000 m. At this stage Yao Jia Shan Mine mainly of a mining area were planning and design, decided to undertake the production, so the main of eight working surface of a mining area, the Shun groove and a mining area on the downhill of rockburst possibility and rockburst risk assessment, combined with Yao Jia Shan mine mining working face mining conditions, the relationship between the coal seam and the geological conditions of whether to have rockburst possibility were analyzed. First through the key strata theory to determine a first mining area mining coal seam of 5(4+5) coal(coal gangue rarely, can be unified mining) first weighting step distance and periodic pressure step distance to determine the stress concentration peak coal seam is burst, and then use FLAC3 D to the danger zone for prediction and verification. According to the above conclusions, the solution to the prevention and control of the means, mainly carried out the following four aspects of research:(1) Through the key strata theory to determine the seam at the top of the key layer and calculate the first breaking distance and cycle breaking distance, in order to estimate the stress value set of coal wall and working face, and then according to the strength theory to determine the upper and lower along the groove of the possibility of impact ground pressure.(2) According experience comparison toassess rockburst risk in working face and upper and lower along the groove,identify high-risk areas, provide the basis for Yao Jia Shan Mine rockburst prevention countermeasures.(3) According to the geological occurrence condition of coal seam dip angle and elevation of mine in the mining area to divide the impact danger zone. FLAC3 D software for coal field to forward the process of simulation, in order todivid work surface and the upper and lower groove where may happen rockburst region.(4) Through the argumentation theory, under the protection layer mining and fully mechanized top coal caving mining influence on rock burst prevention and superiority, to determine the top coal caving mining can prevent rockburst and meet production requirements, develop local impact prevention and control measures, and gives a concrete solution. |
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