Research on Construction Methods for Ultralarge Y-Shaped Tunnel Sections

Table 3

Surrounding rock and supporting structure parameters used in numerical model.

Material	E (MPa)	γ (kN/m^3)	ν	φ/°	c (kPa)
Grade III surrounding rock	10700	24.0	0.26	44	1100
Grade IV surrounding rock	3100	21.5	0.32	32.5	400
Initial support	25000	22	0.2	—	—
Secondary lining	32000	25	0.2	—	—

Notes: E—elastic modulus; γ—volume weight; ν—Poisson’s ratio; φ—internal friction angle; c—cohesion.