Study on Evolution Characteristics of Regenerated Roof Structure in Downward Mining of Bifurcated Coal Seam

Table 4

Material parameters and mixing ratios.

Original rock			Model
Lithology	Stratum thickness (m)	Compressive strength (MPa)	Compressive strength (MPa)	Material ratio		Weight of material (kg)
				Sand : lime : gypsum	Sand	Lime	Gypsum	Water
Mudstone	2.0	20.40	0.124	12 : 3 : 7	27.9	0.7	1.6	3.0
Siltstone	4.0	43.44	0.264	10 : 7 : 3	55.0	3.8	1.6	6.0
Mudstone	1.0	18.50	0.112	12 : 3 : 7	14.0	0.3	0.8	1.5
Fine sandstone	2.0	52.80	0.460	8 : 7 : 3	26.9	2.4	1.0	3.0
Mudstone	2.0	18.40	0.112	12 : 3 : 7	27.9	0.7	1.6	3.0
Siltstone	2.0	41.70	0.264	10 : 7 : 3	27.5	1.9	0.8	3.0
Mudstone	3.0	17.30	0.112	12 : 3 : 7	41.9	1.0	2.4	4.5
Fine sandstone	4.0	71.80	0.460	8 : 7 : 3	53.8	4.7	2.0	6.0
Siltstone	2.0	35.70	0.264	10 : 7 : 3	27.5	1.9	0.8	3.0
Mudstone	9.0	20.50	0.112	12 : 3 : 7	125.6	3.1	7.3	13.6
Fine sandstone	4.0	65.00	0.460	8 : 7 : 3	53.8	4.7	2.0	6.0
Mudstone	5.0	19.20	0.112	12 : 3 : 7	69.8	1.7	4.1	7.6
No. 5-1 coal seam	2.0	6.50	0.038	13 : 4 : 6	28.1	0.9	1.3	3.0
Mudstone	6.0	17.50	0.112	12 : 3 : 7	83.7	2.1	4.9	9.1
No. 5-2 coal seam	1.0	7.30	0.038	13 : 4 : 6	14.0	0.4	0.6	1.5
Mudstone	9.0	18.30	0.112	12 : 3 : 7	125.6	3.1	7.3	13.6
Siltstone	3.0	29.50	0.264	10 : 7 : 3	41.2	2.9	1.2	4.5
Fine sandstone	1.0	55.80	0.460	8 : 7 : 3	13.4	1.2	0.5	1.5
Mudstone	3.0	19.40	0.112	12 : 3 : 7	41.9	1.0	2.4	4.5
Fine sandstone	16.0	76.50	0.460	8 : 7 : 3	215.0	18.8	8.1	24.2
Siltstone	11.0	45.90	0.264	10 : 7 : 3	151.2	10.6	4.5	16.6
Mudstone	6.0	15.50	0.112	12 : 3 : 7	83.7	2.1	4.9	9.1
Fine sandstone	5.0	60.30	0.460	8 : 7 : 3	67.2	5.9	2.5	7.6
Mudstone	5.0	16.80	0.112	12 : 3 : 7	69.8	1.7	4.1	7.6
No. 7-1 coal seam	2.0	8.20	0.038	13 : 4 : 6	28.1	0.9	1.3	3.0
Mudstone	0∼23	18.40	0.112	12 : 3 : 7	137.6	3.4	8.0	14.9
No. 7-2 coal seam	3.0	7.50	0.038	13 : 4 : 6	42.2	1.3	1.9	4.5
Mudstone	3.0	23.36	0.142	12 : 3 : 7	38.9	1.0	2.3	4.2
Fine sandstone	11.0	75.60	0.460	8 : 7 : 3	148.4	13.0	5.6	16.7
Mudstone	2.0	45.07	0.274	10 : 7 : 3	26.7	1.9	0.8	2.9
No. 8-2 coal seam	3.0	8.60	0.407	8 : 7 : 3	35.3	3.1	1.3	4.0
Mudstone	4.0	28.50	0.192	12 : 3 : 7	41.1	1.1	2.6	4.5
Siltstone	2.0	39.70	0.274	10 : 7 : 3	17.2	1.2	0.5	1.9
Fine sandstone	4.0	66.80	0.407	8 : 7 : 3	27.5	2.4	1.0	3.1
Mudstone	4.0	31.57	0.192	12 : 3 : 7	20.0	0.5	1.2	2.2