Breakage Mechanism of Layered Sandstone Penetrated by TBM Disc Cutter
Table 1
The peak force, removed volume, and specific energy for all the tested layered samples.
Number
Inclination α (°)
σ2 (MPa)
σ3 (MPa)
Peak force, 1st (kN)
Peak force, 2nd (kN)
Energy in 1st (J)
Energy in 2nd (J)
Removed volume (cm3)
Specific energy (J/cm3)
0-4-4
0
4
4
392.05
383.21
1336.61
1239.41
15.52
0.38
0-6-4
0
6
4
491.6
139.00
1648.50
433.81
270.81
0.02
0-8-4
0
8
4
608.16
380.52
1769.08
1112.02
164.87
0.04
0-10-4
0
10
4
630.79
132.33
1945.03
352.81
640.93
0.01
30-4-4
30
4
4
464.68
378.13
1374.40
1158.58
14.52
0.40
30-6-4
30
6
4
573.77
543.73
1685.98
1630.39
17.58
0.43
30-8-4
30
8
4
645.98
304.19
1912.62
826.39
177.31
0.04
30-10-4
30
10
4
809.43
411.32
2334.61
1325.17
117.12
0.07
45-4-4
45
4
4
460.19
463
1473.67
1511.53
32.08
0.21
45-6-4
45
6
4
549.83
479.49
1639.90
1296.42
23.59
0.28
45-8-4
45
8
4
710.53
184.44
2036.73
477.04
204.51
0.03
45-10-4
45
10
4
741.99
484.90
2064.67
1374.92
81.62
0.10
60-4-4
60
4
4
502.79
168.37
1669.07
449.65
311.17
0.02
60-6-4
60
6
4
611.52
631.47
1629
2007.56
11.01
0.75
60-8-4
60
8
4
770.79
706.53
2429.14
2174.04
88.03
0.12
60-10-4
60
10
4
826.28
235.48
2694.19
772.88
243.91
0.03
90-4-4
90
4
4
481.30
449.29
1571.29
1351.38
72.84
0.09
90-6-4
90
6
4
640.70
488.92
1935.53
1469.48
43.66
0.18
90-8-4
90
8
4
736.72
300.97
2281.99
809.78
143.61
0.05
90-10-4
90
10
4
862.54
387.57
2692.65
1097.49
171.88
0.05
Note. The a, b, and c symbols of a-b-c for each specimen number indicate the inclination, the maximum principal stress, and the minimum principal stress, respectively.
