Civil Engineering Reference
In-Depth Information
After construction was completed, back analyses and a more detailed interpretation of
monitoring results were carried out. In these analyses the following parameters were
found to be important and were varied in parametric studies:
-
Young's modulus of the shotcrete membrane (E
SC
),
-
horizontal stresses in the claystone (
Δσ
H
),
-
φ
B
and c
B
of the bedding-parallel discontinuities in the claystone,
- deformation moduli E
1
and E
2
of the claystone.
The best agreement with the monitoring results was achieved in an analysis in which
Young's modulus of the shotcrete membrane was selected as E
SC
= 3000 MN/m
2
and
in which
shear parameters
Δσ
H
was reduced from 1.5 MPa in the design analyses to 0.75 MPa (Wittke
et al. 2003). The shear parameters
φ
B
and c
B
of the bedding-parallel discontinuities in
the claystone and the deformation moduli E
1
and E
2
of the claystone complied with the
characteristic parameters specified in Fig. 20.32 (right).
The low modulus of E
SC
= 3000 MPa reflects the fact that, due to the short pullout
lengths and the early closing of the supporting ring, the shotcrete was loaded at a very
young age when it still exhibits a high deformability (Sections 10.5.4 and 20.2.3).
Figure 20.44
Inclinometer measurement at the airport by staff member of WBI
(Tegelkamp et al. 2000)
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