Mechanical Responses to Different Excavation Methods of Qichongcun Tunnel in Guiyang City, China

Table 2

Structural parameters.

Component	Elastic modulus (GPa)	Poisson’s ratio	Bulk density (kN/m^3)
Initial lining	20	0.2	24
Second lining	30	0.3	26
Steel arch	200	0.3	78.5