Behaviors and Overlying Strata Failure Law for Underground Filling of a Gently Inclined Medium-Thick Phosphate Deposit

Table 2

The proportioning table of the model similar material of the No.6 east mining area.

Lithology	Actual thickness (m)	Actual strength (MPa)	Simulated thickness (m)	Simulated strength (kPa)	Similar material ratio (sand : calcium carbonate : gypsum)
Quaternary cover layer	17.47	20.26	7.28	68.56	6 : 7 : 3
Gravel dolomite	59.00	95.86	24.58	323.52	3.5 : 5 : 6
Layered cryptocrystalline dolomite	17.00	88.32	7.08	298.85	3.8 : 5 : 5
Medium to coarse crystalline dolomite	45.00	80.00	18.75	270.69	4 : 2 : 8
Layered argillaceous dolomite	9.00	63.62	3.75	215.27	4 : 5 : 5
Pebbly quartz sandstone	17.80	88.32	7.42	298.85	3.8 : 5 : 5
Industrial phosphate rock	13.31	137.12	5.54	463.98	3 : 2 : 8
Low-grade phosphorus rock formation	21.94	118.00	9.14	399.28	3.2 : 3 : 7
Medium-thick layered dolomite	16.00	101.88	6.67	344.73	3.5 : 3 : 7
Medium-thick primary dolomite	33.50	98.50	13.96	333.29	3.5 : 3.5 : 6.5