Technical Research On Top Coal Weakening Of Large Horizontal Sectional Height In Extremely Steep And Extra Thick Coal Seam

According to the Xinjiang Urumqi mining steeply inclined thick coal seam conditions.Research on weakening technique of fully mechanized top-coal caving in horizontal section of steep inclined ultra thick seam.The main study content is list as follows: through the different methods of coal-rock mass,porosity,coefficient of permeability and water content on the coal mechanical properties change,and the influence of hydraulic fracture parameters and the softening effect.By considering the material non-linear uniformity to simulate the materia l,and the unit to simulate the deformation,damage the weakening of the discontinuous behavior of surrounding rock movement law.Through physical top coal failure of fracture propagation injection conditions simulating model test and theoretical analysis,to determine the axial extension crack crack width and radial crack fracture radius.Through the analysis of blasting,drilling and grouting theory integration structure design and field test,determine fracture blasting orientation and high pressure water injection expansion laws,the weakening of top coal blasting design system integration of drilling and grouting,promoted the development of top coal softening technology.