Study on Stability Control of Retained Gob-Side Entry by Blasting Fracturing Roof Technology in Thick Immediate Roof

Table 2

Mechanical parameters of coal and rock.

Lithology	E (GPa)	σc (MPa)	σt (MPa)		c (MPa)	Ф (deg.)
Silty mudstone	11.3	29	1.8	0.29	6.8	35
Fine sandstone	50.9	86.7	2.8	0.24	13.2	49
Pelitic siltstone	30.4	50.4	2.2	0.28	11.1	36
Coal	5.8	9.1	1.4	0.32	3.4	29
Mudstone	9.7	21.1	1.59	0.3	5.3	32
Medium fine sandstone	46.4	39.5	2.7	0.26	11.7	40