Experimental Study on Energy Evolution and Storage Performances of Rock Material under Uniaxial Cyclic Compression
Table 2
Testing parameters at the unloading point.
Specimen no.
Unloading step
Unloading stress (MPa)
Unloading stress level i
(mJ·mm−3)
(mJ·mm−3)
(mJ·mm−3)
Approach 1
Approach 2
Approach 1
Approach 2
GS-1
1st
8.88
0.10
0.0081
0.0081
0.0043
0.0038
0.0038
2nd
28.46
0.32
0.0447
0.0473
0.0265
0.0182
0.0208
3rd
47.54
0.53
0.0863
0.0992
0.0621
0.0242
0.0371
4th
66.95
0.74
0.1482
0.1695
0.1119
0.0363
0.0576
5th
86.08
0.96
0.2339
0.2682
0.1760
0.0579
0.0922
GS-2
1st
9.14
0.09
0.0078
0.0078
0.0041
0.0037
0.0037
2nd
28.39
0.28
0.0418
0.0445
0.0270
0.0148
0.0175
3rd
47.71
0.46
0.0844
0.0948
0.0623
0.0221
0.0325
4th
67.22
0.65
0.1428
0.1608
0.1100
0.0328
0.0508
5th
86.61
0.84
0.2182
0.2459
0.1709
0.0473
0.0750
GS-3
1st
9.53
0.09
0.0100
0.0100
0.0048
0.0052
0.0052
2nd
30.10
0.30
0.0484
0.0519
0.0309
0.0175
0.0210
3rd
50.74
0.50
0.0972
0.1083
0.0716
0.0256
0.0367
4th
71.21
0.71
0.1614
0.1807
0.1248
0.0366
0.0559
5th
91.64
0.91
0.2476
0.2779
0.1938
0.0538
0.0841
YG-1
1st
20.04
0.10
0.0129
0.0129
0.0088
0.0041
0.0041
2nd
61.63
0.29
0.0624
0.0660
0.0533
0.0091
0.0127
3rd
103.30
0.49
0.1466
0.1554
0.1302
0.0164
0.0252
4th
144.72
0.69
0.2665
0.2812
0.2403
0.0262
0.0409
5th
186.10
0.89
0.4258
0.4483
0.3837
0.0421
0.0646
YG-2
1st
20.05
0.09
0.0123
0.0123
0.0091
0.0032
0.0032
2nd
61.63
0.28
0.0591
0.0618
0.0515
0.0076
0.0103
3rd
102.92
0.47
0.1386
0.1451
0.1241
0.0145
0.0210
4th
144.54
0.65
0.2524
0.2637
0.2281
0.0243
0.0356
5th
185.84
0.84
0.4061
0.4240
0.3650
0.0411
0.0590
YG-3
1st
20.25
0.10
0.0121
0.0121
0.0088
0.0033
0.0033
2nd
61.69
0.29
0.0621
0.0647
0.0545
0.0076
0.0102
3rd
102.92
0.48
0.1455
0.1518
0.1319
0.0136
0.0199
4th
144.52
0.68
0.2673
0.2777
0.2435
0.0238
0.0342
5th
185.88
0.87
0.4284
0.4450
0.3889
0.0395
0.0561
,, and are the total input energy density, elastic energy density, and dissipated energy density of rock specimen under different unloading stress levels i.
