Analysis Of Loose Circle Of Deep Soft Coal And Rock In Different Depth

With the deepening of the excavation depth of the coal mines, the bearing capacity of deep mining rock is also growing, the determination of rock loose circle has become increasingly difficult. The surface deformation of surrounding rock is mainly caused by the breaking of the broken rock in the loose circle, loose circle for quantitative determination of the scope to provide evidence for the appropriate support remained relatively stable. Qualitative analysis deformation factors of coal broken loose rock of the deep mining in theory, qualitative analysis broken loose circle range based on numerical simulation.According to the theoretical analysis of the basic deformation law of circular roadway and rectangular roadway, the surrounding rock failure law is determined, and the qualitative analysis of the loose and broken deformation theory of deep mining coal rock is determined. The main factors that determine the impact of broken rock loose deformation, select the appropriate numerical model. The orthogonal experiment was used to analyze the two factors influenced by the depth of roadway and the section size of the roadway. Take the coal rocks buried depth of 500-1500 m as deep mining standards, the stress of the depth of coal selected 10 mp, 12 mp, 14 pm, 16 mp, 18 mp, 20 mp.coal roadway section selected 6m × 6m, 5m × 5m, 4m × 4m, 3m × 3m. Coal rock selected Ku Zi Dong mine coal rock 11-2. First, laboratory determination of rock mechanical parameters of surrounding rock(number of elastic modulus, Poisson's ratio, cohesive force and internal friction Angle, etc.). Select the commonly used Burge visco elastic model, and make a reasonable division of the grid. Choice of nine direction(as shown in figure 4-3) grid, determine its cohesive force, used to determine the scope of loose circle and plastic ring, according to the different critical points in each direction to draw different depths of loose circle and plastic ring.Based on the results of numerical simulation, analysis of the critical point of the cohesive force of each direction changes, then determine the coordinates to draw each of the orthogonal experiment of the loose circle and the plastic ring, finding out most prone to deformation and instability of the key parts of the section of the roadway surrounding rock, analysis of the conclusion of regularity. To determine the trend and the change rate of loose circle and plastic ring with the depth of the roadway under the condition of different sections, analysis of the regularity of the conclusion.