Bau der u-bahn-linie u3 nord, los 1 in münchen – oberflächensetzungen beim spritzbetonvortrieb mit schirmgewölbesicherungen

The tunnel sections of the Underground Line U3 North, Lot 1 in Munich were constructed by means of the shotcrete method with and without compressed air support. To increase the stability of the working face, tube spiling, jet grouting and injection support was used for various tunnel cross-sections and under different geological conditions. The following article reports on the experience made during construction of the different face support measures and their performance. The results of extensive geodetic and bore-hole-measurements are presented and compared with measurements of earlier tunnel sites with shotcrete lining in Munich.