The Theoretical Study On Cyclone Disaster Caused By Stope Roof Falling Over Great Extent

The disaster of stope roof falling over great extent, happening in the coal face during the course of mining, brings about such comprehensive destruction as energy damage, load lash and cyclone damage. Based on thorough study on the stope roof power lash mechanism and with the theoretical support of hydromechanics and energy, this thesis succeeds in:1) setting up a numerical model where disasters caused by power lash and the lashing blast of compressed air in the stope co-exist when the roof is falling over great extent, working out two formulae in theory: One is about the velocity of cyclone formed in the transportation drift and air return drift; the other is about the applied force objects suffer in windstorm.2) working out the first weighting span and periodic weighting span in longwallsystem ,and proposing some ways to foresee the first weighting and periodic weighting further to prevent main roof flap top in stope form coming into being through controlling the stope weight span.3) analyzing the force-bearing occurrence of the retaining coal columns in camerosystem, working out the calculation formula of the coal column's reasonable dimension , and stating that the calculation formula of cyclone disaster caused by stope roof falling over great extent is the same as that of the wallsystem.4) with abundant theoretical analysis, using FLOTRAN, the model of fluid hydro dynamics in the numerical simulation software of cyclone disaster...