Fracture Mechanical Behavior of Cracked Cantilever Roof with Large Cutting Height Mining

Table 1

Parameters of roofs.

	γ (N/m^3)	σc (×10^6 Pa)	(×10^6 N·m^−3/2)	h (m)
Gabbro	28224	9.8	3.62	2, 3, 4, 5, 6
Granite	25872	7	2.33
Marble	26460	6.5	1.99
Oil shale	15680	3.3	0.37