The Influences of Key Strata Compound Breakage on the Overlying Strata Movement and Strata Pressure Behavior in Fully Mechanized Caving Mining of Shallow and Extremely Thick Seams: A Case Study

Table 1

Coal and rock interface mechanical parameters used in the model.

Strata number	Lithology	Normal stiffness (GPa)	Shear stiffness (GPa)	Cohesion (MPa)	Friction angle (°)	Tensile strength (MPa)
1	Sandy mudstone	1.0	2.5	0	10	0
2	Siltstone	3.5	7.2	0	23	0
3	Sandy mudstone	1.0	2.5	0	10	0
4	Medium sandstone	3.5	7.0	0	20	0
5	Siltstone	3.5	7.2	0	23	0
6	Fine sandstone	4	8.2	0	22	0
7	Gritstone	3.6	8.0	0	14	0
8	Mudstone	0.6	2.3	0	20	0
9	Medium sandstone	3.5	7.0	0	20	0
10	Sandy mudstone	1.0	2.5	0	10	0
11	Siltstone	3.5	7.2	0	23	0
12	Mudstone	0.6	2.3	0	20	0
13	Gritstone	3.6	8.0	0	14	0
14	Sandy mudstone	1.0	2.5	0	10	0
15	Coal	0.5	2.0	0	16	0
16	Fine sandstone	4	8.2	0	22	0
17	Sandy mudstone	1.0	2.5	0	10	0