Self-Tuning Inference Model for Settlement in Shield Tunneling: A Case Study of the Taipei Mass Rapid Transit System’s Songshan Line

Table 2

Results of correlation analysis.

Influential factor		Pearson	Kendall’s tau-b	Spearman’s rho
Shear strength of soils	Coefficient
	P values (ρ)	<0.001	<0.001	<0.001
	N data	999	999	999
Groundwater level	Coefficient	0.046
	P values (ρ)	0.142	0.001	0.003
	N data	999	999	999
Depth of tunnel center line	Coefficient		−0.037	−0.045
	P values (ρ)	<0.001	0.076	0.158
	N data	999	999	999
Tunneling distance	Coefficient
	P values (ρ)	<0.001	<0.001	<0.001
	N data	999	999	999
Chamber pressure	Coefficient	−0.003
	P values (ρ)	0.916	<0.001	<0.001
	N data	999	999	999
Total thrust force	Coefficient
	P values (ρ)	<0.001	<0.001	<0.001
	N data	999	999	999
Tunneling speed	Coefficient	−0.056
	P values (ρ)	0.079	<0.001	<0.001
	N data	999	999	999
Backfill quantity	Coefficient		0.080
	P values (ρ)	0.002	0.074	0.003
	N data	999	999	999
Quantity of excavated soil	Coefficient	0.018		−0.061
	P values (ρ)	0.577	0.041	0.054
	N data	999	999	999
Water pressure	Coefficient
	P values (ρ)	<0.001	<0.001	<0.001
	N data	999	999	999

Correlation significant at the 0.05 level (two-tailed). Correlation significant at the 0.01 level (two-tailed).