| In our country's mining operations,rock burst disasters have serious consequences.The study on the mechanics mechanism of rockburst seismic source is the basis for establishing the accurate prediction system of this disaster.Therefore,it has important theoretical and practical significance to carry out research on the mechanism of rock burst source mechanics.In this paper,based on the moment tensor inversion method and the digital speckle correlation method,the rock fracture type discrimination system is established and verified.Based on this,the mechanical mechanism of rockburst shock source is studied in the outer section of coal mine 513,and targeted anti-scouring measures are proposed to achieve a better effect of early warning and prevention of rockburst.The main research content and conclusions of the paper are as follows:(1)Combining the moment tensor inversion method and the digital speckle correlation method,the framework of the rock failure type discrimination system is constructed.Based on the STA/LTA algorithm,the p-wave first arrival time is judged.The high-precision source location is determined by the double-difference location method.Using MATLAB software,a moment tensor inversion calculation program suitable for rock burst is written.Combining the rock fracture type obtained by DIC and the proportion of the shear part of the moment tensor to determine the rock fracture type identification standard;(2)Based on the Digital Speckle Correlation Method(DIC),the rock uniaxial compression and three-point bending deformation evolution tests are carried out to study the types and characteristics of rock failure.It can be seen from the rock deformation field that the uniaxial compression rock specimens first undergo tensile failure in the upper left and lower right parts.After that,the cracks gradually are expanded to the void area in the middle of the specimen,and tensile and dislocation failures are occurred at the same time.Finally,the crack in the void area is penetrated,and the whole specimen is dislocated and destroyed.The prefabricated crack propagation of the three-point bending rock specimen has obvious stages and discontinuities;(3)Based on the moment tensor and DIC method,the rock fracture type discrimination system is established and verified.By comparing the relationship between the rock fracture type and the proportion of the shear part of the moment tensor,the rock fracture type discrimination system is established.When the shear part of the moment tensor accounts for 0%?45%,the rock specimen will fracture under tension.When the shear part of the moment tensor accounts for 46%?64%,the rock specimens will undergo mixed fracture.When the shear part of the moment tensor accounts for 65% to 100%,the rock specimen will undergo shear fracture.On this basis,the characteristics of acoustic emission parameters of different fracture types and the mechanical mechanism of rock seismic sources are studied to verify the reliability of the rock fracture type discrimination system.(4)Based on the acoustic emission technology and the moment tensor inversion method,the mechanical mechanism of the rock burst source in the outer working face of the 513 outer section of a coal mine is studied.According to the rock fracture type discrimination system,it is analyzed that the three microseismic events in the outer section of 513 working face of a coal mine are roof fracture failure,fault dislocation failure,and roof fracture and fault dislocation coupled failure.In order to effectively prevent the occurrence of rock bursts,targeted prevention and control measures are taken for three rock bursts with different source mechanics.In the subsequent microseismic events,the coal stress before and after the event showed that the prevention and control measures of rock burst proposed in this paper are effective. |
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