Horizontal Subzone Characteristics and Methane Seepage Properties of the Gas Flowing Fracture Zone above the Gob

Table 1

Physical and mechanical properties of rock strata.

Lithology	Elastic modulus E (GPa)	Poisson’s ratio μ	Tensile strength (MPa)	Normal stiffness (GPa·m^−1)	Shear stiffness (GPa·m^−1)	Internal friction angle φ (°)	Cohesion C (MPa)
Siltstone	20.2	0.19	1.3	16.0	12.0	33.5	9.19
Coarse sandstone	25.0	0.19	1.4	18.0	14.0	38.6	9.5
Fine sandstone	15.0	0.20	1.5	21.0	16.0	32.5	5.5
Medium sandstone	35.0	0.15	1.5	20.0	16.0	38.9	10.7
Coal	2.2	0.28	1.0	5.0	3.5	36.5	2.62
Mudstone	2.0	0.24	1.2	9.6	6.2	27	2.32
Sandy mudstone	1.5	0.26	1.3	7.5	4.5	30	3.43