Experimental research on the variational characteristics of vertical stress of soft coal seam in front of mining face

Abstract

Permeability of coal seam is extremely sensitive to the in situ stress loaded. The techniques of “Pressure relief” have been proved significantly effective in practice to improve the gas permeability and the gas extraction rate to the soft coal seam. It is very necessary to make clear of the variational characteristics of the stress distribution in front of coal mining face with the production process. The vertical stress values of the top and bottom layer of the coal seam at different distances in front of the coal face are respectively measured, and the corresponding curves of the vertical stress variation along the mining direction have been obtained. According to the research conclusions in this paper, some available technical measures of “Pressure relief” at different distances and different layers of soft coal seam in front of mining face, are expected to make and to put into practice. The research methods and correlative data included in this paper also can be referred to conduct some further and deep-seated exploration to get new theories and practical techniques for the gas drainage of the soft and low permeability coal seam.