Study on Gas Enrichment Mechanism of Coal Seam Influenced by Vertical Stress on Mountainous Region Condition

Table 1

Calculation parameters.

	Bulk modulus (GPa)	Shear modulus (GPa)	Internal friction angle (°)	Cohesion (MPa)	Tensile strength (MPa)	Density (g·cm^−3)
Sandy mudstone	8	2	24	2.45	1.14	2.51
Fine sandstone	11	9.2	26	2.5	2.4	2.7
Mudstone	6.64	4.18	28	1.95	1.9	2.5
Coal seam	2.9	1.65	20	1.2	0.9	1.48
Coarse sandstone	12	10.8	31	2.9	2.3	2.65
Medium sandstone	11	8	25	3.3	2.2	2.75