Vertical Load and Settlement at the Foot of Steel Rib with the Support of Feet-Lock Pipe in Soft Ground Tunnel

Table 2

Basic parameters of the steel rib and the feet-lock pipe.

Items	Soil grade
	VI	V
Type of steel ribs	I20a	I18
Contact area at the foot of the steel rib (cm^2)	24 × 15	22 × 15
Interval of steel ribs (m)	0.5	0.75
Length of the feet-lock pipe (m)	5	4
Quantity and diameter of the feet-lock pipe at each foot (mm)	6Φ42 × 4
Angle of the feet-lock pipe (°)	30
Young’s modulus of steel ribs (GPa)	206
Radius of steel ribs (m)	6.5
Span of steel ribs (m)	11.47
Height of steel rib (m)	3.44
Young’s modulus of the feet-lock pipe (GPa)	206
Young’s modulus of cement grout (GPa)	23