Research on the Reasonable Width of the Waterproof Coal Pillar during the Mining of a Shallow Coal Seam Located Close to a Reservoir

Table 3

Proportion schemes for similar materials of simulated rock strata.

Parameters	Laterite	Mudstone	Fine-grained sandstone	Mudstone	Fine-grained sandstone	Siltstone	4^−2 coal	Fine-grained sandstone
Density in prototype (g/cm^3)	2.208	2.35	2.67	2.35	2.69	2.7	1.28	2.69
Density in model (g/cm^3)	1.47	1.57	1.78	1.57	1.79	1.80	0.85	1.79
UCS in prototype (MPa)		35.4	50.4	35.4	79.7	71.9	16.43	79.7
UCS in model (kPa)		230.8	332.2	230.8	515.4	468.5	107.9	514.4
Thickness (cm)	25	2.5	4.5	5.5	27.3	2.2	3.5	29.5
Sand : gypsum : lime (: fly ash)	9 : 1 : 9	9 : 2 : 8	9 : 3 : 7	9 : 2 : 8	8 : 2 : 8	9 : 3 : 7	20 : 1 : 5 : 20	8 : 2 : 8
Volume (cm^3)	250000	25000	45000	55000	273000	22000	35000	295000
Total mass (kg)	367.5	39.25	80.1	86.35	488.67	39.6	29.75	528.05
River sand (kg)	174.08	18.59	37.94	40.90	217.19	18.76	12.93	234.69
Gypsum (kg)	19.34	4.13	12.65	9.09	54.30	6.25	0.65	58.67
Lime (kg)	174.08	16.53	29.51	36.36	217.19	14.59	3.23	234.69
Fly ash (kg)							12.93
Water (kg)	36.7	39.2	8.0	8.6	48.9	4.0	3.0	52.8