Research on Permeability Enhancement Model of Pressure Relief Roadway for Deep Coal Roadway Strip

Table 2

Test content and test method.

Test content	Test parameter	Drilling diameter (mm)	Drilling depth (m)	Test method	Remarks
Effect of surrounding rock relief	Destruction	32	9	YTJ20 rock detection recorder
	Displacement	32	9	DW-6 multipoint displacement meter	6 test points per drill hole
Effect of gas extraction	Coal permeability	75	9~21	Radial flow method [44]	Compare with the original coal seam
	Excavation diameter	75	9~21	Statistical analysis [45]