Development and Application of Fluid-Solid Coupling Similar Materials in Discharge Test of Old Goaf Water

Table 2

Strength comparison of some samples in natural state and after immersion.

Group number	Compressive strength (MPa)	Compressive strength of material after 7 days of immersion (MPa)	Strength reduction rate (%)
1	0.2	0.167	20%
7	0.73	0.56	13%
14	0.86	0.77	12%
20	1.46	1.36	9%
25	1.99	1.85	6%