|
Abstract when the upper coal seam adopts retaining coal pillar mining, the working face under the mining pillar, the characteristics of the rock pressure at this time will be obviously different from that of the usual caving mining method. In order to analyze the rock pressure characteristics of coal pillar, the method of field measurement is adopted in this paper. The results showed that the working facee maximum stress is about 7.2 MPa in the upper coal pillar, the stress concentration coefficient is 1.18; in the process of mining affected coal pillar above the range of stress concentration is 14m,the influence scope appears 1 m before pillar mining, eliminates 1m after it.
|