NATM Tunneling - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 646

Figure 20.29 Transition from alternating sequence to the layers comprising
predominantly claystone (Wittke et al. 2006)

In addition to the Lias , the ground profile includes the Knollenmergel and the Rhae-

tian, located underneath the tunnel, as well as the overlying Quaternary layers of cohe-
sive soil at the ground surface on which the airport is founded (Figs. 20.26 and 20.28).
The latter consists mainly of Filder loam and Lias

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residual clay.
West of the tunnel alignment a lake was formerly located in the area of the runway flow-
ing out into a creek running towards the east. In the course of the construction of the
Stuttgart airport the area of the lake and the creek was filled up. The existing partially
soft and settlement-sensitive valley deposits, however, remained under the fill. The fill
and the valley deposits are locally several meters thick (Fig. 20.30).
In the northern part of the airport the groundwater table of the alternating sequence is
mostly located within the overlying Quaternary layers (Figs. 20.26 and 20.28). In the ad-
jacent section up to the southern limit of the airport the groundwater table prevailingly
lies within the alternating sequence (Fig. 20.26).
The tunnel is thus located, almost over its entire length, completely underneath the
groundwater table. The maximum height of the water table above the tunnel's invert is
reached in the area of the airport runway with around 26 - 27 m (Fig. 20.28).

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