Study on the Evolution Characteristics of Two-Zone Failure Mode of the Overburden Strata under Shallow Buried Thick Seam Mining

Table 1

Physical and mechanical parameters of the model.

No.	Histogram	Compressive strength (MPa)	Modulus of elasticity (GPa)	Poisson’s ratio	Compressive strength of model (kPa)
1	Aeolian sand	11.6	12	0.30	69.6
2	Clay	15.3	20	0.30	91.8
3	Gritstone	36.6	35	0.25	219.6
4	Sandy mudstone	22.8	23	0.28	219.6
5	Siltstone	40.6	35	0.25	243.6
6	Mean-grained sandstone	45.3	33	0.28	271.8
7	Fine-grained sandstone	44.6	32	0.28	267.6
8	Coal seam	10.5	15	0.35	63