Evolution of Mining-Induced Stress in Downward Mining of Short-Distance Multiseam

Table 1

Physical and mechanical parameters of rock and coal samples used in the numerical simulation.

No.	Lithology	Thickness/m	Density/(kg/m^3)	Bulk modulus/GPa	Shear modulus/GPa	Cohesion/MPa	Friction angle/(°)	Tensile strength/MPa
1	Roof strata	50.0	2600	3.33	2	0.85	30	1.22
2	Fine sandstone	8.5	2794	20.14	16.27	3.8	43	6.75
3	Sandy mudstone	2.5	2520	10.76	5.7	1.18	35	1.17
4	8-1 coal	3.0	1420	1.9	0.93	0.2	20	0.28
5	Sandy mudstone	9.4	2446	10.76	5.7	1.18	35	1
6	Sandy mudstone	6.6	2417	10.76	5.7	1.18	35	1.64
7	7-1 coal	2.6	1370	2.8	1.2	0.6	27	0.4
8	Sandy mudstone	13.5	2549	10.76	5.7	1.18	35	1.31
9	Mudstone	2.5	2437	4.3	2.8	0.7	30	1.8
10	6-1 coal	2.5	1390	2	0.88	0.42	24	0.3
11	Mudstone	4.1	2545	5.8	3.2	1.2	30	3.25
12	Fine sandstone	2.0	2800	16.04	12.02	3.47	43	4.96
13	Coarse sandstone	5.9	2700	7.35	6.63	3.04	40	4.34
14	Fine sandstone	3.0	2800	16.04	12.02	3.47	43	4.96
15	5-2 coal	1.6	1410	1.73	0.82	0.18	20	0.2
16	Fine sandstone	3.0	2597	15.28	11.2	3.1	42	3.48
17	5-1 coal	1.1	1410	1.73	0.82	0.18	20	0.2
18	Fine sandstone	3.6	2586	18.02	14.02	3.8	43	5.13
19	Sandy mudstone	3.8	2520	4.9	3.2	1.18	35	1.8
20	Mudstone	2.8	2567	4.3	2.8	0.7	30	1.68
21	4-1 coal	3.1	1460	2.12	0.93	0.5	24	0.35
22	Mudstone	2.8	2463	3.94	2.6	0.68	30	0.98
23	Floor strata	20.0	2463	3.94	2.6	0.68	30	0.98