Study on Geostress Measurement by Hydrallic Fracturing Method in Mine Soft Rock Roadway

Abstract：In order to obtain the mine deep geostress information and to reveal the geostress features and the variation law with the depth increased, a hydraulic fracturing method was applied to the geostress test conducted in the main transportation roadway extended below the No. 3 level of Pingmei No. 1 mine. Meanwhile, the strain releasing method was applied to the site measurements of the geostress in different depth 7 roadways and the distribution features of the geostress in the mining area were obtained. The results showed that after the deep mining operations conducted, the mine was a high geostress zone, the max main stress in the mining area was 31.70 MPa, the max main stress was in a horizontal direction and the mine was mainly controlled by the structural stress. Three main stresses were all in a linear increased relationship to the mining depth, the increasing extent of the max main stress in the three was obvious and the pressure gradient was 2. 75 MPa/hm. According to the geostress distribution conditions obtained, scientific and rational sapport and reinforcement measures were conducted to the mine roadway and the disasters control of the mine high geostress zone was realized.