Failure Characteristics and Deformation Control Methods of the Bottom Drum of Roadways during Repeated Mining of Multiple Coal Seams

Table 1

Physical and mechanical parameters of rock mass of each formation in the simulation area.

Number	Lithology	(kg/m^3)	(GPa)	(MPa)	(MPa)		(°)
1	Siltstone	2500	17.0	8.9	6.0	0.22	39.5
2	Silty mudstone	2400	8.5	3.6	3.0	0.25	36
3	1# coal	1400	5.0	1.5	1.5	0.28	28.5
4	Fine-sandstone	2550	10.0	11.4	6.5	0.18	37.5
5	3# coal	1400	5.0	1.5	1.5	0.28	28.5
6	Silty mudstone	2400	8.5	3.6	3.0	0.25	36
7	5-2# coal	1400	5.0	1.5	1.5	0.28	28.5
8	Mudstone	2100	6.5	3.0	2.1	0.27	30.0
9	Silty mudstone	2400	8.5	3.6	3.0	0.25	36
10	5-3# coal	1400	5.0	1.5	1.5	0.28	28.5
11	Mudstone	2100	6.5	3.0	2.1	0.27	30.0
12	Fine-sandstone	2550	10.0	11.4	6.5	0.18	37.5
13	7# coal	1400	5.0	1.5	1.5	0.28	28.5
14	Fine-sandstone	2550	10.0	11.4	6.5	0.18	37.5
15	Mudstone	2100	6.5	3.0	2.1	0.27	30.0