Application of the Ultimate Hanging Arch Length of the Layered Roof with Anchors and the Gob-Side Entry Retaining

Table 2

Lithology and physical and mechanical parameters of the roof of the entry.

Terrane	Lithology	Body force (kN/m^3)	Seam thickness hi (m)	Elasticity modulus Ei (GPa)	Strength of extension Rti (MPa)	Compressive strength Rci (MPa)
1	Mudstone	26	1.6	15	2.5	65
2	Fine sandstone	25.6	2.25	35	6.6	106
3	Mudstone	26	2.76	15	2	95
4	Fine sandstone	27	1.04	35	8	82
5	Mudstone	25	5.81	16	7	75