Overburden Migration and Failure Characteristics in Mining Shallow Buried Coal Seam with Thick Loose Layer

Table 4

Mechanic parameters of coal seam and rock strata.

Lithology	E (GPa)	μ	φ (°)	c (MPa)	σt (MPa)
Aeolian sand	0.22	0.37	3	0.03	0.0023
Coarse sandstone	1.14	0.34	21	0.63	0.0033
Medium sandstone	1.63	0.31	19	0.96	0.0058
Fine sandstone	2.44	0.35	20	1.30	0.0170
Sandy mudstone	1.06	0.37	12	0.42	0.0100
Coal seam	0.28	0.42	10	0.12	0.0006