Mechanical Properties of Sandstone Roof and Surrounding-Rock Control of Mining Roadways Subject to Reservoir Water Disturbance

Table 5

Mechanical parameters of joint.

Lithology	Normal stiffness (GPa)	Tangential stiffness (GPa)	Cohesion (MPa)	Internal friction angle (°)	Tensile strength (MPa)
Fine sandstone	2.8	1.7	0.3	30	0.4
Mudstone	2.1	1.3	0.2	28	0.3
Coal	0.9	1.5	0.1	28	0.2
Medium sandstone	3.5	2	0.4	33	0.5