Study on Law of Overlying Strata Breakage and Migration in Downward Mining of Extremely Close Coal Seams by Physical Similarity Simulation

Table 2

Mechanics parameters of the similar rock material.

		Prototype		Model
Number	Lithology	Bulk density (g/cm^3)	Compressive strength (MPa)	Bulk density (g/cm^3)	Compressive strength (MPa)
1	Fine sandstone	2.54	75.3	1.588	0.941
2	Siltstone	2.64	50.5	1.65	0.631
3	Fine sandstone	2.54	75.3	1.588	0.941
4	Sandy mudstone	2.2	30.2	1.375	0.377
5	Siltstone	2.64	44.2	1.65	0.553
6	Mudstone	2.22	32	1.388	0.400
7	Medium sandstone	2.54	85	1.588	1.063
8	Mudstone	2.22	30.1	1.388	0.377
9	Coal 9	1.4	9.5	0.875	0.119
10	Sandy mudstone	2.2	30.2	1.375	0.377
11	Coal 10	1.4	9.5	0.875	0.119
12	Siltstone	2.64	50.5	1.65	0.631