Research On Rock Burst Rules And Prevention Near Fold

The rock burst is one of the dynamic catastrophe phenomena in the coal mining. The research has shown that rock burst usually happens near the folds, which influences the production and the safety of the coal mines seriously. Therefore, the study on the regulation of rock burst near the folds and its control is significant to make sure the safty production in the coal mines.This paper (thesis) analyzes the fold formation and its influence on initial stress based on the geology dynamics. It is believed that the local concentrated stress superimposed by abutment pressure ahead of working face and residual tectonic stress is one of the most important reasons causing rock burst near folds. By the experimental research, the burst tendency and the electromagnetic emission rules of both the pure and the moist coal samples during the deformation and fracture are studied.There are many reasons for fold rock burst, such as the fold effect on abutment pressure ahead of working face, residual tectonic stress released by the coal mining, and the rock burst due to tectonic stress caused by the fold. By numerical analysis of the influence factors about fold rock burst, we can find that the abutment stress concentration coefficient KV of the working face of underhand advance is larger than that of overhand advance with the same distance to the fold axis, and the maximum horizontal stress concentration coefficient Kh of the former one is smaller in the beginning, but then it increases gradually and finally exceeds that of latter one. When the syncline axis working face advances first and then the syncline wing working face advances, the Kh and KV of the seam close to syncline decrease in different degrees.However, adopting the opposite advanced sequence,both of the KV and Kh increases largerly. Therefore, we can confirm that the risk of rock burst is higher when the working face advances form the fold swing, and also the risk is higher when the working face advances underhand from the anticline axis if both of the syncline and anticline exist.Choose the Yanbei Mine 250205 top working face as a practice field, carrying out the forecast and active measures against fold rock burst. The practice shows that the electromagnetic emission method can be used to forecast rock burst very well and the relieving shot and seam infusion can reduce the intensity of rock burst effectively, even eliminate the risk.