Model of Overlying Strata Structure in Large Mining Height Excavating Condition and Calculation of Support Working Resistance

Table 4

The physical and mechanical characteristics of the roof combination of cantilever structure of No. 8218 large mining height working face.

Serial number	Lithology	Density kg/m^3	Thickness (m)	Tensile strength (MPa)	Top plate force (MPa)	Breaking step (m)	Weight of broken block (MN)
6	Fine sandstone	2438	1.60	4.06	0.09	4.90	1.21
5	Sandy shale	1426	3.10	2.47	0.11	1.56	0.32
4	Medium sandstone	2453	9.20	5.21	0.22	3.80	1.66
3	Coarse sandstone	2683	9.00	6.22	0.44	15.47	3.40
2	Fine sandstone	2645	2.30	4.06	0.59	8.88	1.34
1	Sandy shale	2468	0.90	2.47	0.05	3.43	0.16
	Coal seam	1476	4.14