The invention discloses a
hydraulic fracturing and grouting solidification combined rock cross-
cut coal uncovering method which includes that when roadway drivage reaches a 10m
coal layer
vertical distance, fracturing holes of a
coal layer are drilled, the coal layer is subjected to
hydraulic fracturing, and the water injection amount reaches the preset value after above 3MPa pressure drop appears in fracturing; a plurality of grouting holes are drilled when the roadway drivage reaches a 5m coal layer
vertical distance; coal layer
methane gases are extracted through the fracturing holes and the grouting holes; the coal layer is subjected to quantitative grouting through the grouting holes with grouting pressure to be above 15MPa; and roadway drivage is continued after grouting solidification, and rock cross-
cut coal uncovering is completed.
Single hole grouting amount includes grouting hole grouting amount M1 and coal layer
permeation grouting amount M2 and is calculated according to M=M1+M2=rho*eta / K *(pi*D<2> / 4 *L +pir<2>*l*P)*10<-6>, wherein rho is a grouting density, eta is a storage coefficient, K is a grouting foaming
expansion rate, D is a drilling
diameter, L is grouting hole length, r is a penetration
radius of
slurry in the coal layer, l is length of the grouting holes in the coal layer and p is a coal layer
porosity. The
hydraulic fracturing and grouting solidification combined rock cross-
cut coal uncovering method has the advantages of being capable of fast and safely performing rock cross-cut coal uncovering, avoiding re-handling, and improving social benefit.