Experimental Study on Deformation and Acoustic Emission Characteristics of Arch Roadway under Different Unloading Rates

Table 2

Effects of unloading rates on AE hits rate and damage variable under different initial geostresses.

Initial geostresses (MPa)	Unloading rates	AE average hits rate at the unloading stage	Deviatoric stress at the peak of AE hits rate (MPa)	Relative damage proportion at the unloading stage (%)	Relative damage proportion at static creep stage after unloading (%)
10	Rapid	14.85	8.5 (85%)^1	4.9	15
	Slow	1.16	7.35 (73.5%)^1	8	7
20	Rapid	25.02	18.6 (93%)^1	3.5	20.1
	Slow	3.48	18.1 (90.5%)^1	11.5	10.4
30	Rapid	100.3	28.5 (95%)^1	3.4	48.1
	Slow	12.56	30 (30 s after unloading)^1	20.5	27.8