[Retracted] Mining Stress Distribution in Stope and Overlying Rock Fracture Characteristics and Its Disaster-Pregnant Mechanism of Coal Mine Earthquake

Table 1

Physical and mechanical parameters of coal and rock.

Lithology	Density/(kg•m^−3)	Elasticity modulus/GPa	Poisson ratio	Uniaxial compressive strength/MPa	Cohesion/MPa	Internal friction angle/°
Siltstone	2630	11.47	0.26	7.74	13.72	41.17
Mudstone	1650	8.41	0.21	3.26	6.51	33.18
Medium-grained sandstone	2580	12.97	0.25	11.32	16.81	42.25
Sandy mudstone	1960	9.71	0.23	4.38	8.71	38.86
Coal	1430	2.21	0.21	1.12	1.96	30.48
Clay rock	1550	3.46	0.22	2.86	4.79	33.31