Application Research On Borehole Acoustic Method Measuring The Mine Ground Stress

Mine stress measuring is of great significance for roadway layout and safety production in coal mine.In combination with the development of in-situ stress measurement technique,the article points out the limitations in existing several mine ground stress measuring methods under deep complex geological conditions.Based on previous scholars study of rock acoustic elasticity theory,borehole acoustic method is discussed to measure the mine ground stress according to the theory and the existing acoustic technology.By reference the rock elasticity theory based on finite deformation of continuum mechanics,the relationship between wave velocity and stress is analyzed and used as theoretical basis of the borehole acoustic method in measuring ground stress. As complex coal mine geological conditions,the work way,data processing and data interpretation of borehole acoustic methods is researched. The Determination of scheme of mine roadway borehole acoustic method is designed.The field test was carried out in a mine in Huainan,the author acquired the wave velocity in sandstone in the same layer,and made the wave velocity ellipse fitting; the in-situ stress state of a certain mine working face is successfully calculated and analysised through combination of the wave velocity and rock mechanical parameters.Stress field is analyzed, through the contrast with results of stress release method.The experimental results indicate that:(1) The extreme value of wave velocity in horizontal and rock tectonic stress state have consistency,the change of vertical wave is mainly determined by the stress in this direction rather than the stress of in the perpendicula direction.(2) The size of the wave velocity in rock mass are greatly influenced by tectonic stress and roadway driftage, wave velocity anisotropy in the plane is the result of joint action of stress in different directions.(3) The borehole acoustic method can measure the size of the the station’s three principal stress value and direction,it have been achieved in the mine test and get a good effect.Through field test,the borehole acoustic method can successfully measure the mine ground stress, it is a simple,rapid and quantitative evaluation way to measure in-situ stress, it can for provide reliable references in the on-site detection and the interpretation of results.