Application of the Upper-Bench CD Method in Super Large-Span and Shallow Tunnel: A Case Study of Letuan Tunnel

Table 4

The mechanical parameters of rock mass and supporting structure.

Category of materials	Volumetric weight (kN·m^−3)	Modulus of elasticity (GPa)	Poisson’s ratio	Cohesion (kPa)	Internal friction angle (°)
Rock mass	2	1	0.35	500	21
Grouting reinforcement zone	2	1.05	0.35	550	22
Initial support		30.5	0.2
Temporary support		29.5	0.2
Feet-lock bolt	7.8	210	0.3
Secondary lining	2.5	31	0.2
Backfilling of inverted arch	2.3	18	0.2