Study on Large Deformation Prediction and Control Technology of Carbonaceous Slate Tunnel in Lixiang Railway

Table 3

Medium term forecast results.

Monitoring cycle (d)	Peripheral convergence (mm)	BP neural network model		GA-BP neural network model
		Estimate (mm)	Relative error (%)	Estimate (mm)	Relative error (%)
31	686.2	669.4	2.45	696.7	1.53
32	694.7	707.9	1.90	702.6	1.14
33	699.2	713.8	2.09	710.6	1.63
34	702.5	719.4	2.41	711.8	1.32
35	705.6	721.8	2.30	713.9	1.18
Average relative error			2.23		1.36