Research on the Technology of Weakening Hard Coal Mass Strength through Hydraulic Fracture

摘要

Technologic problems and possible inducing disaster in fully mechanized top coal carving for hard thick coal seam were analyzed in this paper. The technical principle of hydraulic fracture weakening for hard coal-rock mass and its multifunction effect including strength weakening, reducing dust, pre-releasing gas and preventing coal spontaneous combustion were analyzed. It was presented that hydraulic fracture weakening strength for hard coal-rock mass is an effective technology insuring safe and high efficient mining under hard thick and high gas coal seam. Current research of the technology was analyzed. It was put forward that crack expanding law of hydraulic fracture in coal-rock mass, structure alteration of fissured rock mass by seepage pressure and its macromechanics response and envelop bore technology of fissured rock mass hydraulic fracture weakening are the key technique and direction to further research.