Use of the Equivalent Mining Height Method for Understanding Overlying Strata Movement and Stress Distribution in an Isolated Coal Pillar

Table 1

Parameters of mechanical properties and material ratios.

Serial number	Lithology	Actual thickness (m)	Model thickness (cm)	Compressive strength (MPa)	Simulated strength (kPa)	Weight of material (kg)
						Sand	Lime	Gypsum	Water
1	Gritstone	33	25	23.0	137.72	267.19	46.76	20.04	37.11
2	Clay rock	21	16	11.0	65.87	183.21	9.16	21.38	23.75
3	Siltstone	15	11	14.0	83.83	110.21	18.37	18.37	16.33
4	Fine sandstone	13	10	28.0	167.66	106.88	13.36	13.36	14.84
5	Clay-sandstone	7	5	13.0	77.84	57.25	2.86	6.68	7.42
6	Fine sandstone	3	2	28.0	167.66	21.38	2.67	2.67	2.97
7	Siltstone	5	4	16.0	95.81	40.08	6.68	6.68	5.94
8	Medium sandstone	5	4	25.0	149.70	44.53	2.67	6.23	5.94
9	Fine sandstone	3	2	28.0	167.66	21.38	2.67	2.67	2.97
10	Clay rock	4	3	11.0	65.87	34.35	1.72	4.01	4.45
11	Siltstone	7	5	16.0	95.81	50.10	8.35	8.35	7.42
12	Clay and sandstone interbedded	7	5	13.0	77.84	57.25	2.86	6.68	7.42
13	Siltstone	4	3	16.0	95.81	30.06	5.01	5.01	4.45
14	Medium sandstone	4	3	25.0	149.70	33.40	2.00	4.68	4.45
15	Clay rock	4	3	11.0	65.87	34.35	1.72	4.01	4.45
16	Gritstone	7	5	23.0	137.72	53.44	9.35	4.01	7.42
17	Fine sandstone	3	2	28.0	167.66	21.38	2.67	2.67	2.97
18	Medium sandstone	5	4	25.0	149.70	44.53	2.67	6.23	5.94
19	Clay-sandstone	3	2	13.0	77.84	22.90	1.15	2.67	2.97
20	Gritstone	5	3	23.0	137.72	32.06	5.61	2.40	4.45
21	Siltstone	4	3	16.0	95.81	30.06	5.01	5.01	4.45
22	Coal	4	4	11.1	66.41	45.80	5.34	2.29	5.94
23	Fine sandstone	5	4	28.0	167.66	42.75	5.34	5.34	5.94
24	Medium sandstone	16	12	25.0	149.70	133.59	8.02	18.70	17.81