| Most coal mines in our country have entered the deep mining stage, with the mining depth increasing rock burst accidents increased year by year, caused significant casualties and economic losses. Many domestic and foreign scholars study support method to improve the impact resistance of the rock burst roadway, but the supporting mechanism is still not very clear. The application effect of steel support and other forms of passive support in rock burst roadway is not ideal. As the active and flexible support form, bolt has natural advantage to support the rock burst roadway.Study the bolt supporting mechanism in rock burst roadway by theoretical analysis and numerical simulation. Using the energy theory, the theory of limit equilibrium zone found that:(1) Support need to increase the strength of the coal and rock mass;(2) Support need to increase the coal and rock deformation, and the support system must adapt to that deformation;(3) Supporting system should can increase the residual strength of coal significantly, reduce the residual strength attenuation speed;(4) Today's high strength bolt can satisfy the requirement of the weak rock burst roadway supporting.Using Griffith strength theory, mohr strength theory derivation: anchorage body compressive strength, shear strength,residual compressive strength and residual shear strength increase with the bolt strength. The damage mechanic model of coal and anchorage body is established based on damage mechanics, found that:(1) The ultimate strength and residual strength of anchorage body are improved after bolt supporting;(2) The key of bolt supporting in rock burst roadway is elongation;(3) Improve the bolt tensile strength can increase the anchorage body compressive strength, residual strength, reduce the anchorage body softening modulus, lower anchorage body rock burst orientation. Using finite difference software FLAC3 D to simulate the longgu coal mine support situation, and found that: Bolt support can effectively control the impact of the roadway damage, reduce the scope of the plastic zone of surrounding rock, improve the strained condition of surrounding rock, and decrease the roof subsidence and both sides deformation quantity.Determine the longgu coal mine 7303 workface are weak rock burst roadway by comprehensive index method. Use the electromagnetic radiation method for testing after bolt support, and found good supporting effect were obtained. |
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