Calculation Method of Overburden Damage Height Based on Fracture Mechanics Analysis of Soft and Hard Rock Layers

Table 8

Overlying stratum damage height calculation accuracy by 4 methods.

Working face	Actual measurement of overburden damage height	“Three down” procedure		Fitting formula with multifactors		Key layer theory		Method in this paper
		Calculation	Relative error	Calculation	Relative error	Calculation	Relative error	Calculation	Relative error
N1102	53.46 m	46.05 m	13.86%	60.83 m	13.79%	75.33 m	40.91%	51.44 m	3.78%