Variation of Rock Mass Pressure during Tunnel Construction in Phyllite Stratum

Table 9

Fitting correlation coefficient between rock mass pressure and distance from the tunnel face.

Function types	Results	Y0	Y3	Y4	Y5	Y6
Logarithmic function	Correlation coefficient R^2	0.931	0.737	0.067	0.468	0.910
Logistic function	Correlation coefficient R^2	0.982	0.764	0.323	0.711	0.952
Multiple functions	Correlation coefficient R^2	0.975	0.837	0.425	0.737	0.941