Effects of Cyclic Loading on the Pore Structure of Anthracite Coal

Table 1

Loading conditions for the cyclic loading tests.

Group	Test condition		Loading time (h)
	Loading frequency (Hz)	Pressure amplitude during loading (MPa)
1	10	12–18	6
2	7
3	4
4	7	10–20
5		14–16
6	—	15
7	—	—	—

Note. In the test groups 1–5, only the frequency or amplitude was changed; in the control group 6, the frequency or amplitude was fixed; in the blank control group 7, cyclic fatigue loading was not performed.