Based On Particle Flow Software To Research On Loosening Circle In Deep Soft Coal Rock Roadway

Coal mining is becoming more and more difficult to support after reaching the deep part of the soft coal and rock roadway is loose and broken. Take the loose circle of deep soft coal roadway under high ground stress as the research object, through the numerical simulation of particle flow software to determine the physical and mechanical parameters of coal rock. Different lateral pressure ratio, different level, different roadway,multi-factor, multi-level modeling ? monitoring wall departmen the top of the stress,displacement value. After the treatment and combined with the model loose and broken,the rules of the loose circle expansion and change, the shape characteristic rule of loose circle, the partition failure feature of loose circle, the method of depth of loose circle.With the increase of mining depth, the surrounding rock loose circle expanding. But in the depth of the critical depth above the surrounding rock loose circle depth not big,after the destruction of the surrounding rock of roadway loosening can remain stable.When the depth occurred in the roadway below critical depth loose after the destruction of roadway, loose circle depth increase, play their own capacity is still not stable in the surrounding rock. In the absence of supporting conditions, roadway deformation will be close to.The results obtained from the simulation can be assumed that the equivalent stress of the roadway is larger than that of the uniaxial compressive strength of rock when the roadway is in the stress field. The depth of the roadway is the critical depth, and the following is the deep part of the roadway.Loose circle form depends on the compression ratio and the stress field of roadway at depth. When the tunnel depth above the critical depth, sidewall and the top of the loose circle depth ratio close to lateral pressure than the reciprocal; when the tunnel depth below the critical depth, and away from the tunnel sidewall center distance and the top of the loose circle depth and distance of roadway center distance ratio close to the pressure side than the last. Which side ratio is not equal to the moment, the loose circle is an oval shaped,oval and long axis parallel to the direction of minimum stress. The surrounding rock loose circle in the long axis end to produce a large number of shear diagonal cracks, resulting in a large number of circumferential cracks in short shaft; lateral pressure ratio is equal to a loose round shape, only a small amount of shear crack and circular crack. When the roadway is below the critical depth, the depth of the top of the top will be larger than the bottom due to the gravity effect. Loose coil performance as a whole up.when tunnel is below critical depth, surrounding rock loose circle formed easily broken partition In the stress diagram, the radial stress in a section of the loose circle is first decreased and then increased, and the circumferential stress first increases and then decreases. The radial stress curve is concave and the circumferential stress curve is convex.In order to identify the occurrence of partition fragmentation in the loose circle.Distinguishing method of loose circle depth ralate to critical depth. When the tunnel depth above the critical depth, the loose circle broken through stress range is small, unable to get accurate value, should adopt different displacement point discriminant loose circle size. The depth of the inflection point is the depth of the loose circle. When the depth of the roadway is below the critical depth, the broken area is large, especially after the failure of the zone. The failure of the rock mass affected the displacement of the loose body. This should be used in stress measurement of different point values. When the surrounding rock stress reaches or exceeds a point is a loose circle.