Mechanisms of Floor Heave in Roadways Adjacent to a Goaf Caused by the Fracturing of a Competent Roof and Controlling Technology

Table 1

Strain-softening parameters for chain pillar material.

Initial parameters		Strain (mm/mm)	Postpeak parameters
Parameter	Value		Cohesion (MPa)	Friction angle (°)
Density (kg/m^3)	1400	0	1.3	25
Bulk modulus (GPa)	1.5	0.025	0.9	22
Shear modulus (GPa)	1.2	0.050	0.7	20
Cohesion (MPa)	1.3	0.075	0.5	18
Friction angle (°)	25	0.010	0.4	16
Tension strength (MPa)	0.43	1.0	0.4	16