TBM Tunneling - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 673

The support in the machine area of a Gripper TBM is accomplished by steel sets, steel
meshes, rock bolts and shotcrete. Steel sets and meshes are installed as a headgear, nor-
mally immediately behind the cutterhead and the finger shield, using a ring erector and
a wire mesh erector. With drilling equipment, boreholes for rock bolts, exploration dril-
lings and advancing support with spiles or grouting can be carried out. The support of
the entire cross-section will usually be completed in the backup area.
21.1.4 Lining Concepts
The lining concepts that are used today for machine tunneling in rock, are represented
in Fig. 21.12 in combination with the corresponding type of TBM.
Figure 21.12 TBMs and corresponding lining concepts (Wittke et al. 2006)
Using a Gripper TBM, tunnels can be driven without a lining if this is not required
for static reasons. Locally, such as in jointed or weathered rock mass sections, a sup-
port consisting of rock bolts, steel fabric mats, steel sets or shotcrete can be applied.
If for esthetical or operational reasons a smooth tunnel contour is required, a lining
of shotcrete or cast-in-place concrete can be installed subsequently. Also a double
lining consisting of a shotcrete membrane and an internal lining of cast-in-place con-