Variation of Rock Mass Pressure during Tunnel Construction in Phyllite Stratum

Table 7

Correlation coefficient between rock mass pressure and excavation time.

Function types	Results	Y0	Y3	Y4	Y5	Y6
Logarithmic function	Correlation coefficient R^2	0.931	0.538	0.067	0.478	0.911
Logistic function	Correlation coefficient R^2	0.982	0.796	0.323	0.704	0.952
Multiple functions	Correlation coefficient R^2	0.975	0.826	0.425	0.742	0.942