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

Table 1

Pressure relief coefficients (%) at the center line of the roadway and coal seams at two sides.

	Vertical distance /m
	7	9	12	15	18	21
0	52.0–4.6	31.4–5.0	17.7–4.7	11.3–4.9	7.8-2.7	5.8–2.3
0.25	32.6–2.9	19.7–3.2	11.1–2.7	7.1–3.1	4.9-2.2	3.6–2.0
0.5	23.6–2.1	14.3–2.2	8.0–2.2	5.1–2.2	3.6-2.0	2.6–1.9
Two sides	6 m	7 m	8 m	8 m	5 m	5 m