Coal Engineering ›› 2022, Vol. 54 ›› Issue (2): 98-104.doi: 10.11799/ce202202018

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Characteristics of microseismic spatio-temporal precursory information of rockburst in a shallow working face with hard roof

  

  • Received:2021-06-04 Revised:2021-07-23 Online:2022-02-14 Published:2022-07-06
  • Contact: 雅荣 雅荣薛 E-mail:bernicexue@126.com

Abstract: In order to improve the pertinence of the implementation of on-site prevention and control measures in rock burst mines, taking I010203 working face of B2 coal seam in a shallow buried hard roof coal mine as the engineering background, the temporal and spatial evolution law of microseismic monitoring information before and after the occurrence of previous large energy tremors was studied. The results show that: the focal position of large energy tremors in I010203 working face are affected by the upper "knife handle" goaf boundary, which have stage characteristics, and mainly concentrated in the middle and lower part of the working face, section coal pillar and surrounding rock of lateral goaf. Vertically, it is mostly located in coal and roof rock, and the fracture of hard roof is the main inducing factor of rock burst; within 7 days before the occurrence of the large energy tremor, the b value of the microseismic precursor warning factor, the A(t) value of the total fault area and the S value of the microseismic activity suddenly decrease or increase, respectively, and keep the low value or high value anomaly, indicating that the elastic energy accumulation and fracture degree increase in the coal and rock mass, and the rockburst risk increases; the microseismic factor contour drawn with spatially smoothed seismicity method presents certain regularity before the occurrence of large energy tremors, which can further quantify the local rockburst risk area. The research results reveal the spatio-temporal precursory information characteristics of rock burst under hard roof conditions, which can guide the field personnel to take targeted measures for rockburst risk, and contribute to the accurate prevention and control of rock burst in coal mine.

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