A Study on Excavation Characteristics of Tunnel with Upper-Soft Lower-Hard Stratum

Table 2

Basic physical and mechanical parameters for the lower “hard” formation.

Sampling depth	Rate of weathering	Bulk density	Grain density	Compressive strength		Internal friction angle	Cohesion	Elasticity modulus	Poisson’s ratio
				Nature	Saturation
h; (m)		(g/cm^3)	(g/cm^3)	-nature	-saturated	(°)	(kPa)	(GPa)
				(MPa)
97.5~102.5	Weakly weathered	2.75	2.79	49.9	46.85	42	45	11.6	0.3