Ground Settlements due to Construction of Triplet Tunnels with Different Construction Arrangements

Table 3

Overview of the soil parameters used for tunnel sequences (Schotte et al. [24]).

Soil parameters
Soil gradation
Sand (%)	77
Silt (%)	07
Clay (%)	16
Bulk density, γb (kN/m^3)	17
Saturated soil density, γsat (kN/m^3)	19.8
Tangent stiffness modulus, (MPa)	3
Effective cohesion, c′ (MPa)	2 ∗ 10^−3
Effective angle of friction, Ø′ (degrees)	34.3
Effective angle of dilatancy, ψ′ (degrees)	4.3
Poisson ratio,	0.3
Active earth pressure coefficient, Ka	0.28
Initial shear modulus, (MPa)	94
Relative density, Dr (%)	50
Unloading-reloading stiffness modulus, (MPa)	90
Power indicating the stress-level dependency of the stiffness, m	0.544
Shear strain level at which the secant shear modulus (Gs) is reduced to 72.2%, γ0.7	1.5 ∗ 10^−4
Failure ratio, Rf	0.938