The Stability of Gob-Side Entry Retaining in a High-Gas-Risk Mine

Table 2

Material parameters.

Feature of rocks	Bulk modulus (GPa)	Shear modulus (GPa)	Cohesion (MPa)	Poisson ratio	Density (kg·m^−3)	Tensile strength, st (MPa)
Medium sandstone	6.9	3.3	3.2	0.27	2690	2.2
Siltstone	8.8	4.8	3.3	0.23	2750	2.5
Limestone	3.6	2.1	2.0	0.22	2250	1.5
Coal	2.5	1.6	1.5	0.35	1350	1.1
Mudstone	3.7	2.1	2.1	0.22	2360	1.5
Medium sandstone	6.9	3.3	3.2	0.27	2690	2.2
Siltstone	8.8	4.8	3.3	0.23	2750	2.5