Tunnel Back Analysis Based on Differential Evolution Using Stress and Displacement

Table 6

Results of back analysis on a segment-lined tunnel using stress and displacement.

Case	(GPa)	(MPa)	(°)	Error rate (%): (I – B) ÷ B × 100 (%)			Average error rate (%)	Displacement (mm) stress (MPa)
				Reference	Input (I)			—	—	—	—	, : true displacement observation; , :true stress observation; , : trial displacement at convergence; , : trial stress at convergence
0.5	0.25	35.0
Case C-1	Output (B)			−7.41	8.70	−4.37	6.82	Index
	0.54	0.23	36.6					1	−2.6	−1.5	−2.5	−1.4
								2	−2.7	−2.1	−2.5	−1.9
								3	−2.4	−2.4	−2.3	−2.3
								4	−2.1	−2.7	−2.0	−2.5
								5	−1.5	−2.6	−1.4	−2.5
								Index
								1	12.3	7.4	12.4	7.4
								2	11.8	8.5	11.9	8.4
								3	12.3	7.4	12.4	7.4
Case C-2	0.45	0.26	37.2	11.11	−3.85	−5.91	6.96	Index
								1	−3.8	−1.1	−4.0	−1.1
								2	−3.5	−2.1	−3.7	−2.2
								3	−2.9	−2.9	−3.0	−3.1
								4	−2.1	−3.6	−2.1	−3.7
								5	−1.1	−3.9	−1.1	−4.0
								Index
								1	13.5	9.1	13.2	9.3
								2	13.4	9.3	13.2	9.4
								3	13.5	9.1	13.2	9.3
Case C-3	0.44	0.26	37.3	13.64	−3.85	−6.17	7.88	Index
								1	−7.3	−3.4	−8.8	−3.6
								2	−7.0	−5.5	−8.3	−6.4
								3	−6.6	−6.3	−7.8	−7.4
								4	−5.9	−6.7	−6.9	−7.8
								5	−3.6	−7.0	−4.1	−8.3
								Index
								1	31.0	13.1	30.6	13.4
								2	31.7	13.9	31.0	14.1
								3	31.0	13.1	30.6	13.4