Researches on the Excavation Disturbance of Shield Tunnel in Sandy Cobble Ground

Table 1

Calculation parameters.

Soil layer	Density (g/cm^3)	Elastic modulus (MPa)	Poisson’s ratio	Cohesion (kPa)	Internal friction angle (kPa)	Permeability coefficient (m/s)
Clay	1.81	6.13	0.3	21	20
Cobble	2.2	55	0.23	1	42
Cobble	2.2	60	0.23	2	42