The Coal Pillar Width Effect of Principal Stress Deflection and Plastic Zone Form of Surrounding Rock Roadway in Deep Excavation

Table 4

The variation law of the maximum failure depth position in plastic zone pillar.

Roof	Width of coal pillar	Deflection direction	Deflection angle
	4 m~8 m	Coal wall	10°~13.5°
	8 m~12 m	Coal wall	2°~2.5°
	12 m~16 m	Coal pillar	1°~1.5°
	16 m~20 m	No change	0°
Coal pillar	Width of coal pillar	Deflection direction	Deflection angle
	4 m~12 m	Roof	0.5°~8.5°
	12 m~16 m	Roof	10°~13°
	16 m~18 m	No change	0°
	18 m~20 m	Roof	4°
Floor	Width of coal pillar	Deflection direction	Deflection angle
	4 m~8 m	Coal pillar	0.5°~6.5°
	8 m~10 m	No change	0°
	10 m~14 m	Coal pillar	0.5°~1.5°
	14 m~20 m	No change	0°
Coal wall	Width of coal pillar	Deflection direction	Deflection angle
	4 m~6 m	Floor	12°
	6 m~10 m	Roof	10°~12°
	10 m~14 m	Roof	3°~5°
	14 m~20 m	No change	0°