Prediction Model of Failure Zone in Roadway Sidewall considering the Lithologic Effect of Rock Formation

Table 1

Physical-mechanical parameters of weak soft rock in western China.

Rock layer	Seam thickness h/m	Strength of coal seam		Deformation; parameters of; coal-rock body		Lateral coefficient; λ	Supporting strength /MPa
		C/MPa	ϕ/°	α	β
unstable	8	1	15	0.7	0.5	0.6	0.05
relatively stable	6	3	24	1.5	0.7	0.5	0.10
stable	4	5	35	2	0.8	0.4	0.25