Numerical Simulation of the Volumetric Strain Distribution of a Protected Coal Seam

Table 2

Mechanical parameters of coal and rock.

Lithology	Density/kg/m^3	Bulk modulus/GPa	Shear modulus/GPa	Friction angle/°	Cohesion/MPa	Dilatancy angle/°	Uniaxial tensile strength/MPa
Sandy mudstone	2740	3.7	3.1	35	2.6	10	2.4
Mudstone	2690	2.0	1.5	31	1.5	10	1.0
Fine sandstone	2740	3.5	2.2	30	2.0	10	2.0
Coal	1450	1.0	0.8	20	0.6	10	0.5
Limestone	3080	3.9	3.5	43	4.8	10	3.2