Munich:

Underground Railway Line U3-South, Construction Lot 5

Description

This lot commenced at Thalkirchen station near the river Isar & rose with an incline of 40 ‰. up the adjacent Sendlinger slope as far as Obersendling on the high bank 20 m above.

Four headings were driven, using the tunnelling method with shotcrete lining, at the foot of the slope in the middle of the section. Having begun in tertiarymarl, the western part ended entirely in quarternary gravel, where the upper aquifer was lowered. The eastern part entered tertiary flinz sand, where the lowering of the groundwater was restricted to the tertiary sands. During driving the crown advanced approx. 2-4 m ahead of the bench & bottom closure.

The outer shell was supported by shotcrete & steelmesh across the entire cross section, with additional arches in the crown. Upon the completion of the driving work the inner shells of the tunnel were shotcreted using a formwork transport wagon.