Near-fault mining induced microseismic distribution characteristics and its influencing factors

Abstract

Mining near the fault structure can easily lead to the fault activity and induce serious geological disasters, posing a serious threat to coal mine safety production. To reveal the surrounding rock activity characteristics induced by near-fault mining, taking Qixing Coal Mine in China as the engineering background, the contrastive analysis of the microseismic events in the fault-control area and the mining disturbance area was conducted based on the microseismic monitoring data. From the point of views of seismic parameter b value and focal-mechanism solution, the microseismic event distribution characteristics and the fracture modes in those two areas were analyzed. With the mining area increasing, the evolution characteristics of the microseismic events in the surrounding rock affected by the near-fault structures were verified by using FLAC3D. We found that b value in the fault-control area was much lower than that in the mining disturbance area, indicating that the possibility of large-magnitude microseismic events was greater in the former than that in the latter. Moreover, the principal stress difference and the elastic energy in the mining area displayed the discontinuity distribution charateristics. The results showed that there were some threshold values making the microseismic event numbers change rapidly with these factors variation such as mining depth, rock strength and initial stress field. The conclusions are of important theoretical and practical value for the similar mining engineering.

Keywords

• fault
• microseismic monitoring
• mining engineering
• numerical simulation
• parameter analysis