Study on Deformation Mechanism and Supporting Countermeasures of Compound Roofs in Loose and Weak Coal Roadways

Table 2

Numerical calculation parameters.

Rock formation name	Bulk density (g.cm^−3)	Uniaxial compressive strength (MPa)	Uniaxial tensile strength (MPa)	Cohesion (MPa)	Internal friction angle (°)	Elastic modulus (GPa)	Poisson’s ratio
Fine sandstone	2650	37	3.15	6.5	30	32	0.29
Siltstone	2500	32	2.81	3.7	36	28	0.30
Coal	1400	12	1.43	1.5	18	21	0.38
Shale	1900	18	1.86	2.1	33	26	0.42