Study on Dynamic Evolution of Roof Crack and Support Timing of Secondary Tunneling for Large Section Open-Off Cut in Deep Mines

Table 2

Calibration of mechanical properties of rock strata and coal seams used in the model.

Rock strata	Matrix properties		Contact properties
	Density (kg/m^3)	E (GPa)	(GPa/m)	(GPa/m)	Cohesion (MPa)	Friction angle (°)	Tensile strength (MPa)
Sandy mudstone	2450	3.42	180	54.2	2.7	32	1.23
Fine sandstone	2550	5.40	278.5	83.6	3.4	35	1.59
Coal	1400	0.79	150.2	46.1	1.4	30	0.52