Experimental and Numerical Study of Rock Stratum Movement Characteristics in Longwall Mining

Table 2

Mechanical parameters of rock mass.

Lithology	ρ (kg/m^3)	EC (GPa)	kn/ks	(GPa)		μ	(MPa)	(MPa)
Fine sandstone	2872	8	1.6	8	1.2	0.63	40	40
Siltstone	2698	7	1.6	7	1.2	0.60	35	35
Mudstone	2512	2	1.6	2	1.2	0.50	10	10
Sandy mudstone	2578	3	1.6	3	1.2	0.40	15	15
Coal	1371	1.2	1.6	2	1.2	0.40	8	8

Note: ρ in the table is the density of the particles; E_C is the elastic modulus of the particles; k_n/k_s is the ratio of the normal and tangential stiffness of the particles; is the elastic modulus of the parallel bond; is the ratio of the normal and tangential stiffness of parallel bonds; μ is the coefficient of friction between the particles; is the normal bond strength of the parallel bond; is the tangential bond strength of the parallel bond.