Engineering geology aspects for design and classification - Tunnel Engineering: Basics and Additional Services for Design and Construction - page 87

Figure 2-29 Example of tunnelling class TBM 2 [43].
Fig. 2-30 illustrates an example of a classification for shield machines according to the
DGGT recommendations. The example shows a tunnelling situation with special meas-
ures (drilling) to probe the ground from the machine. The support consists of a closed ring
of reinforced concrete segments installed in the protection of the shield skin. The division
into sub-classes is intended to refine the classification, for example to taken into account
increasing difficulties. This covers defined, project-specific specialities.
Figure 2-30 Example of tunnelling class SM-V1.2 [43].