Stability Analysis and Fracture Patterns of Hard Main Roof in Longwall Top Coal Caving with Large Mining Height

Table 3

Material mixture ratio and the parameters of the similar model.

Lithology	Thickness (cm)	Bulk density (g/cm^3)	UCS (MPa)	Mixture ratio (sand : cement : plaster)	Total weight (kg)	Sand (kg)	Cement (kg)	Plaster (kg)	Water (kg)
Glutenite	20	1.69	0.04	13 : 1 : 0	9.33	8.66	0.67	0.00	0.37
Fine-grained sandstone	20	1.50	0.17	6 : 7 : 3	9.33	8.00	0.93	0.40	0.37
Medium conglomerate	5	1.53	0.14	8 : 7 : 3	11.66	10.37	0.91	0.39	0.47
Fine-grained sandstone	10	1.58	0.17	6 : 7 : 3	9.33	8.00	0.93	0.40	0.37
Fine-grained sandstone	10	1.69	0.10	10 : 8 : 2	9.33	8.48	0.68	0.17	0.37
Fine-grained sandstone	10	1.72	0.17	6 : 7 : 3	9.33	8.00	0.93	0.40	0.37
Siltstone	4	1.53	0.06	10 : 9 : 1	9.33	8.48	0.76	0.08	0.37
Coarse-grained sandstone	4	1.69	0.10	10 : 8 : 2	9.33	8.48	0.68	0.17	0.37
Fine conglomerate	1	1.63	0.15	8 : 7 : 3	4.67	4.15	0.36	0.16	0.19
Fine-grained sandstone	6	1.66	0.17	6 : 7 : 3	9.33	8.00	0.93	0.40	0.37
Medium-grained sandstone	1	1.67	0.14	8 : 7 : 3	4.67	4.15	0.36	0.16	0.19
Fine conglomerate	4	1.63	0.15	8 : 7 : 3	9.33	8.29	0.73	0.31	0.37
Coarse-grained sandstone	2	1.69	0.10	10 : 8 : 2	9.33	8.48	0.68	0.17	0.37
Fine-grained sandstone	3	1.66	0.17	6 : 7 : 3	7.00	6.00	0.70	0.30	0.28
Siltstone	1.5	1.50	0.06	10 : 9 : 1	7.00	6.36	0.57	0.06	0.28
Medium conglomerate	2	1.56	0.14	8 : 7 : 3	4.67	4.15	0.36	0.16	0.19
Sandy mudstone	1	1.61	0.03	10 : 1 : 0	4.67	4.24	0.42	0.00	0.19
3–5 coal seam	3.75	0.89	0.02	9 : 8 : 2	8.75	7.87	0.70	0.17	0.35