Study on the “Pressure Relief and Yielding Support” Joint Prevention and Control Technology for the Weak Impact Roadway in the Extremely Thick Coal Seam

Table 1

Numerical calculation of mechanical parameters of the coal and rock.

Coal and rock	Tensile strength (MPa)	Compressive strength (MPa)	Elastic modulus (MPa)	Poisson’s ratio	Internal friction angle	Cohesion (MPa)	Density (kg/m^3)
Coarse sandstone	0.69	9.61	1,991.5	0.235	46.3	2.72	2,397
Argillaceous sandstone	0.77	5.43	1,026	0.241	45	1.83	2,144
No. 3 coal seam	0.21	6.20	1,140	0.266	32	1.78	1,280