Pressure Relief and Permeability Enhancement Mechanism of Short-Distance Floor Roadway in Deep Coal Roadway Strip

Table 3

Pressure relief effect of the overlying coal seam in the floor roadway at different positions.

/m	Effective pressure relief zone 1/m	Effective permeability enhancement zone 0/m	Permeability enhancement ratio	Gas permeability enhancement ratio	Pressure relief effect
7	4.3	12.1	0.28–6.06	11.1–239.3	Obvious
9	3.5	15.4	0.17–2.26	6.7–89.2
12	1.2	20.5	0.09–0.94	3.6–37.1
15	0.3	20.7	0.06–0.23	2.4–9.1	Unobvious
18	0	20.5	0.03–0.14	1.2–5.5
21	0	20.4	0.02–0.04	0.8–1.6