Research Article

Research on the Influence of the Key Stratum Position on the Support Working Resistance during Large Mining Height Top-Coal Caving Mining

Table 1

The mechanical parameters of contact surface of coal and rock.

LithologyNormal stiffness (GPa)Shear stiffness (GPa)Cohesion (MPa)Internal friction angle (°)Strength of extension (MPa)

Packsand8.58.51.620.20
Medium-grained sandstone7.07.01.519.50
Argillaceous sandstone6.06.0014.50
No. 8 coal seam5.55.5013.50
Medium-grained sandstone8.58.51.520.20
Argillaceous sandstone7.57.51.019.50
Mudstone6.06.0014.50
No. 13 coal seam5.55.5013.50
Sandstone8.58.51.520.20