Application of a FBG-Based Instrumented Rock Bolt in a TBM-Excavated Coal Mine Roadway

Table 1

Results of rock bolt pull-out experiment.

Axial force (kN)	Wavelength shift (nm)
	FBG 1	FBG 2	FBG 3	FBG 4	Average
10	0.0596	0.0565	0.0524	0.0548	0.0558
20	0.1595	0.1552	0.1564	0.1588	0.1575
30	0.2593	0.2588	0.2543	0.2598	0.2581
40	0.3594	0.3561	0.3518	0.3425	0.3525
50	0.4592	0.4593	0.4577	0.4618	0.4595
60	0.5589	0.5551	0.5615	0.5588	0.5586
70	0.6629	0.6632	0.6699	0.6675	0.6659
80	0.7623	0.7685	0.7646	0.7594	0.7637
90	0.8622	0.8665	0.8594	0.8749	0.8658
100	0.9632	0.9649	0.9654	0.9656	0.9648