Civil Engineering Reference
In-Depth Information
If segmental linings are used, the following additional assumptions are
made in the analysis:
•
Pre-deformations of the segmental linings resulting from the erection
of the segments are proportional to the elastic deformations.
•
The annular gap between the ground and the lining is completely
grouted.
•
Linearized theory of second order (small strain, large deformations) can
be applied.
B.3 Required equations and calculation process
The calculation of the internal forces of the analytical model is carried out
using the displacement method. This requires that the primary stress situation
or the stresses determined from the earth pressure approach is used as a load
displacement condition, where the, as yet unknown, deformations (in this
case the deformation of the tunnel contour) are assumed to be zero.
However, as additional limitations of the deformations do not exist, the
forces due to the earth pressure are not in equilibrium around the tunnel
contour. Furthermore, the deformations along the tunnel contour are not
equal to zero. Instead, these can be calculated taking into account the
appropriate forces - the transition condition between the perforated disc
σ
h
r
p
r
τ
R
ϕ
r
σ
ϕ
p
t
M
Q
N
w
v
p =
p +
r0
p
r2
σ
v
r
p =
t
p
t2
σ
h
Figure B.3
Definitions of the parameters
