Study on Reasonable Chain Pillar Size in a Thick Coal Seam

Table 2

Model parameters.

Lithology	Tensile strength/MPa	Cohesion/MPa	Friction/°	Bulk modulus/GPa	Shear modulus/GPa
Mudstone	1.25	1.70	26.44	0.82	0.49
Sandstone	1.51	1.47	23.16	0.70	0.46
Siltstone	1.43	3.14	35.85	1.07	0.77
Coal	0.72	1.99	26.81	0.35	0.14