Study of the Construction Sequence of Overlapping Tunnels by the Shield Tunneling Method: A Case Study of the Longest Overlapping Tunnel in China

Table 2

Numerical simulation parameters.

	Poisson’s ratios	Bulk modulus K (MPa)	Shear modulus G (MPa)	Density (kg/m^3)
Segment	0.17	1.57 × 10^4	1.295 × 10^4	2500
Grouting layer	0.2	4.57 × 10^2	3.96 × 10^2	2500