preliminary design and analysis for an immersed tube tunnel across

⎟ ⎛ 35 ⎞
N cor = N ⋅ ⎜
(3.4.a)
⎝ p + 7 ⎠
where, N is the SPT value obtained from the field, p′ is the effective overburden
pressure in
2
t /m unit and can be calculated by the following formula.
'
p′ = γ ⋅h
(3.4.b)
where, h is the half of the height between the sea level and the rock layer in meter, and
γ ' is the effective density of the soil in
formula,
3
t / m and it can be calculated from the following
γ ' = γ − γ
(3.4.c)
where, γ sat is the density of the saturated soil and γ w is the density of the sea water.
sat
w
18