Research On The Occurrence Mechanism And Prevention Of Compression Type Rock Burst In Xinzhouyao Mine

Rock burst is a phenomenon that suddenly coal was fiercely destroyed, which main show is that a large number of coal been fling at roadway suddenly, and destroyed a few even100meters of the roadway or the coal face instantly, causing stent wreck, roof sinking and floor expansion and so on. Due to its complex formation mechanism and a multitude of influence factors, rock burst is a difficult problem of the research in coal mine exploiting. In Xinzhouyao mine of Datong, coal mine’s roof, floor and coal seam are very hard, and most place of occurring rock burst have not geological structure. In this condition, a little of rock burst occurrence mechanism and criterion has been reported. This paper has summarized what we have got results, combined the mining condition and what rock burst happened of Xinzhouyao mine in Datong with case analysis, site measurement, laboratory experiment, theoretical analysis, numerical simulation and field test method to research the occurrence mechanism and prevention of rock burst. The main contents and results are as follows:(1) Xinzhouyao mine has worked as a test mine. We have investigated its development form, its geological condition of mining area, its mining technology condition, rock burst occurred condition and so on, kept the time, place, strength, damage and casualties of what have happened and recorded all rock burst, and detailed analyzed the typical one. The general characteristics of rock burst in Xinzhouyao mine have been summarized, this occurred condition and influencing factors in three-hard conditions have been analyzed, and rock burst type been made sure as coal compression type rock burst.(2) Used five model analyzed the deformation and destruction law of hard coal seam and hard roof, floor strata by the method of theoretical analysis, concluded that elasto-plastic damage model might be suitable for the actual conditions. This model has been inferred on the base of analyzing the occurrence mechanism of coal compression type rock burst in three-hard conditions.(3)8935working face in west2panel Xinzhouyao mine has worked as a test part. The rock physical and mechanical experiments, the impact tendency experiments, the similar material experiments and numerical experiments have been made, then we mastered the physical and mechanical properties and the impact tendency of roof, floor strata in Xinzhouyao mine, and studied the motion law and the deformation damage law of coal seam, roof and floor in three-hard conditions; moreover, provided base data for the occurrence mechanism and prevention on rock burst.(4) According to the statistics, theoretical analyses and experimental result of rock burst, the changing pressure area imbalance theory on compressive type rock burst of coal in three-hard conditions has been build. This theory said that compressive type rock burst caused by the damage of coal dynamic balance in the changing pressure soften damage zone and changing pressure harden elastic-plastic zone under the variable load. This theory explained that some area in coal seam having same impact tendency may happen rock burst under same mining conditions, and some do not.(5) According to changing pressure area imbalance theory, we have researched and applied some technology by actual conditions of Xinzhouyao mine, the comprehensive index method, the SOS microseismic monitoring method, the mine pressure analysis and forecast method, the KBD5electromagnetic radiation law and the drilling five forecast method; the construction relief pressure hole, the open-cut relief pressure slot and relief pressure blasting relief pressure method; the force caving roof and proximal surface broken roof shift pressure method; the relatively strengthen coal by strengthening advance support method; the airport roadway coal pillar and strengthen support method; and avoiding the two wings of the face mining at the same time and worker avoid the danger zone method etc. Occurrence frequency of rock burst in Xinzhouyao mine has declined from50in2009to10-20times in today, the number of expulsion coal has declined from10-150t to under l0t. At the end, raising the six words policy of synthetical utilize technique on compressive type rock burst in three-hard conditions:"measure, relief, support, break, care, avoid".