Large-Deformation Failure Mechanism of Coal-Feeder Chamber and Construction of Wall-Mounted Coal Bunker in Underground Coal Mine with Soft, Swelling Floor Rocks

Table 1

Physical and mechanical parameters of surrounding rock and concrete.

Strata	Density (kg·m^−3)	Bulk modulus (GPa)	Shear modulus (GPa)	Friction angle (°)	Cohesion (MPa)
Coarse-grained sandstone	2600	5.0	4.0	28	2.0
Fine-grained sandstone	2500	4.0	3.0	26	1.7
Siltstone	2550	3.5	2.5	24	1.5
Coal seam #4-2	1400	1.3	0.9	18	0.3
Mudstone	1800	2.0	1.5	25	0.7
Clay	1500	2.0	1.3	23	0.4
Reinforced concrete	2700	5.0	4.0	32	2.2
Interface	kn = ks = 125 (GPa/m)