Study On Ground Stress Of Second Level And It's Influence To The Roadway Deformation Of LuLing Coal Mine

The surrounding rock deformation of roadway is mainly controlled by the rock' strength and the ground stress, but the ground stress is the fundamental force, and the most important external conditions. In second level of Luling coal mine, the deformation and destruction of roadway is very severe and consequently the efficient production is badly hindered. In this mine, however, ground stress measuring and study about the way the stress effect the tunnel's deformation and construction is very little. Exploring the distribution rule of ground stress, finding out the relationship between the tunnel strain and ground stress is surely very meaningful to the efficient production of Luling mine.By analyzing the roadway strain data of second level in Luling coal mine systematically, measuring ground stress by AE, numerical simulatiing for stress field of second level by FLAC 3D, theory and numerical simulation analysis for the roadway's deformation, it was concluded that the features of tunnel deformation was mainly given by the distribution of ground stress, and the paper also inferred:(1) The level of ground stress in Luling mine was high. In second level, the maximum principal stress ranged from 20MPa to 34MPa and the minimum principal stress ranged from 7MPa to 12MPa. The stress reduced around the faults.(2) The maximum principal stress mainly directed to west and east, which was accorded to the stress background of east of China. And the direction of stress varied around the faults and became perpendicular to the faults.(3) In second level of Luling coal mine, the maximum principal stress differed by horizon obviously. In number two and four mining areas, the stress was greatest, in number one, three and five areas, the stress reduced, in number six and eight areas, the stress was lest.(4) The maximum principal stress increased along the depth, but the rate varied. From surface to 425m deep, the growth rate was 4.66MPα/100m, from 425m to 975m, the rate was 2.3MPα/100m, and the general rate was 3.37MPα/100m.(5) In second level of Luling coal mine, under the stress background, the deformation of the roadway tended to be large, varied in every mining area. And the maximum principal's direction caused the deformation of tunnels directing from west to east was less than those directing from north to south.(6) In second level of Luling coal mine, in fact, the number of constructing points were large, and the construction covered every mining area and the deforming value was high. The deforming time was long. And the deformation of tunnels directing from north to south was much more severe than those directing from west to east.(7) By comparing of the features of the ground stress and tunnel deformation, it was concluded, in this paper, that the features of tunnel deformation was mainly controlled by the distribution of ground stress.(8) According to the stress background of this mine, the roadway should put in the sandstone or siltstone. And the important and long serving—time tunnel should direct from west to east. In number two and four mining areas, the supporting strength should be greatest.