128 Ground improvement by deep vibratory methods
Key assumptions of this method are that shear stresses are zero at the
unit cell perimeter, that they are also zero at the surface and bottom of each
incremental slice, and that no relative deformation occurs between column
and soil. In Section 4.6.1, a sample calculation of this method in comparison with the Priebe method is presented.
Division of unit cell into n increments
Computation of settlements increments i = 1 to n
Plastic analysis
Elastic analysis
Start values
Δp′ and Δσ v,B
Startvalue
Δσ v,B
Computation of strains
Computation of strains
no
yes
Computation of factor F
yes
no
yes
no
yes
no
Computation of average earth
pressure value K of the soil
′
′
Δp′ = Δp
Δp′ = Δp
Δσ
B
′ = Δσ v
Δσ
B
′= Δσ v
Δσ
B
′ = Δσ v
Δσ
B
′ = Δσ v
S Increment = (ε v,el + ε v,pl )∗h
S Increment = ε v,el ∗ h
ε v,el + ε v,pl > ε v,el
i S column = ∑S Increment
n
1
Δσ v =
p − ε v ∗ E
s A s
A B
B
s
B
Δσ v =
(A s )
−K Komb ∗ σ
B
FK +
(A B )
(A s ∗K p )
(P + σ v , 0 A s )
s
v,0
B
B
B
B
v
v
v
v
⎛
⎝
Δp =
Δσ
B
1 + 2K 0
1+ K + K 0
⎛
⎝
K if K > 1
1 if K < 1
v
⎣
⎡
⎤
⎦
Figure 4.15 Computational steps of the Goughnour and Bayuk method.