Study on the Prediction of the Height of Two Zones in the Overlying Strata under a Strong Shock

Table 4

Main coal and rock mechanical parameters.

Number	Lithology	Bulk density (kN/m^3)	Tensile strength (MPa)	Elastic modulus (GPa)	Internal friction angle (°)	Cohesion (MPa)	Poisson’s ratio
1	Fine-grained sandstone	2.21	1.56	1.415	25.48	2.40	0.17
2	Siltstone	2.45	0.78	0.885	15.3	4.90	0.23
3	Conglomerate	2.64	3.02	0.345	34.72	2.91	0.19
4	Sandstone	2.35	0.88	0.925	11.8	3.47	0.25
5	Medium-grained sandstone	2.31	1.12	1.214	27.77	1.32	0.22
6	Sandy mudstone	2.54	0.23	0.346	26.28	0.48	0.27
7	Coarse-grained sandstone	2.41	0.48	0.817	30.84	1.65	0.25
8	Mudstone	2.62	0.95	1.321	27.21	1.88	0.25
9	3-2# coal seam	1.35	1.33	1.67	29.74	2.68	0.31
10	4-2# coal seam	1.45	1.86	1.84	30.87	3.61	0.21