Study on the Key Factors of Terminal Mining Line Layout in Repeated Mining of Close-Distance Thick Coal Seams

Table 3

Mechanical parameters of coal and rock mass in calculation model.

Layer	Natural density (kg/m^3)	Shear modulus (GPa)	Bulk modulus (GPa)	Cohesion (MPa)	Internal friction angle (°)	Tensile strength (MPa)
Coarse sandstone	2580	8.40	11.23	3.40	32	1.50
Fine sandstone	2612	8.24	11.79	5.83	33	2.60
Siltstone	2300	4.26	5.79	2.53	31	1.20
1# coal seam	1550	3.36	4.51	1.50	27	0.80
Fine sandstone	2612	8.24	11.79	3.73	31	2.50
Medium-fine sandstone	2580	7.90	9.30	5.20	32	1.40
Carbonaceous mudstone	2360	4.35	5.87	3.80	29	1.20
2# coal seam	1550	3.36	4.51	1.50	27	0.80
Carbonaceous mudstone	2360	4.35	5.87	2.80	29	1.80
Medium-fine sandstone	2580	7.90	9.30	2.40	32	1.30