Variation of Rock Mass Pressure during Tunnel Construction in Phyllite Stratum

Table 8

Range of parameters for rock mass pressure and excavation time.

Function types	Basic form	Parameters	Value range
Logarithmic function			−52.439∼0.017
			−5.248∼−0.084
			−24∼119.254
Logistic function			0.014∼0.026
			0.021∼0.233
			456.969∼638.652
			5.339∼11.030
Multiple functions			−0.006∼0.086
			−0.0004∼0.0004
			−0.00001∼0.00002
			−0.00002∼0.00005