TBM Tunneling - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 705

Figure 21.44 Flysch H1
Applied TBM
The heading was carried out with a second-hand shielded TBM with a boring diameter
of 11.8 m and an internal diameter of 11.6 m in the area of the tail skin. The clear di-
ameter of the double-track railway line amounts to 10.8 m. Consequently, a maximum
thickness of the segmental lining of 40 cm resulted. This was a key requirement for the
design.
Two injection holes exist at the invert of the shield for annular gap grouting. In the
area of the sidewalls and the roof the annular gap can only be filled through injection
holes in the segments. Here both the grouting of mortar and pneumatic injection of pea
gravel was possible.
Design of the segmental lining
Segmental rings with a thickness of 40 cm consisting of six regular stones and one key-
stone (Figs. 21.45 and 21.46) as well as three ring positions 1 to 3 shown in Fig. 21.46
were designed. Position 3 had to be installed in every second ring to avoid persistent
longitudinal joints.