Rock Burst Mechanism under Coupling Action of Working Face Square and Regional Tectonic Stress

Table 2

Thickness of coal and rock strata.

Number	Lithology	Thickness (m)	Accumulated thickness of roof (m)
1	Medium sandstone	4.2	93.7
2	Siltstone	6.9	89.5
3	Medium sandstone	3.7	82.6
4	Siltstone	3.1	78.9
5	Mudstone	6.5	75.8
6	Medium sandstone	11.3	69.3
7	Siltstone	7.4	58
8	Mudstone	8.2	50.6
9	Siltstone	5.3	42.4
10	Medium sandstone	9.5	37.1
11	Sandstone	4.9	27.6
12	Mudstone	4.2	22.7
13	Medium sandstone	1.6	18.5
14	Siltstone	8.9	16.9
15	Fine sandstone	5.5	8
16	Siltstone	2.5	2.5
17	Coal	6.5	—
18	Siltstone	3.6	—
19	Fine sandstone	19	—